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Sample records for experimental functional neurosurgery

  1. Experimental and clinical standards, and evolution of lasers in neurosurgery.

    PubMed

    Devaux, B C; Roux, F X

    1996-01-01

    From initial experiments of ruby, argon and CO2 lasers on the nervous system so far, dramatic progress was made in delivery systems technology as well as in knowledge of laser-tissue interaction effects and hazards through various animal experiments and clinical experience. Most surgical effects of laser light on neural tissue and the central nervous system (CNS) are thermal lesions. Haemostasis, cutting and vaporization depend on laser emission parameters--wavelength, fluence and mode--and on the exposed tissues optical and thermal properties--water and haemoglobin content, thermal conductivity and specific heat. CO2 and Nd-YAG lasers have today a large place in the neurosurgical armamentarium, while new laser sources such as high power diode lasers will have one in the near future. Current applications of these lasers derive from their respective characteristics, and include CNS tumour and vascular malformation surgery, and stereotactic neurosurgery. Intracranial, spinal cord and intra-orbital meningiomas are the best lesions for laser use for haemostasis, dissection and tissue vaporization. Resection of acoustic neuromas, pituitary tumours, spinal cord neuromas, intracerebral gliomas and metastases may also benefit from lasers as accurate, haemostatic, non-contact instruments which reduce surgical trauma to the brain and eloquent structures such as brain stem and cranial nerves. Coagulative lasers (1.06 microns and 1.32 microns Nd-YAG, argon, or diode laser) will find an application for arteriovenous malformations and cavernomas. Any fiberoptic-guided laser will find a use during stereotactic neurosurgical procedures, including image-guided resection of tumours and vascular malformations and endoscopic tumour resection and cysts or entry into a ventricle. Besides these routine applications of lasers, laser interstitial thermotherapy (LITT) and photodynamic therapy (PDT) of brain tumours are still in the experimental stage. The choice of a laser in a

  2. Experimental new automatic tools for robotic stereotactic neurosurgery: towards "no hands" procedure of leads implantation into a brain target.

    PubMed

    Mazzone, P; Arena, P; Cantelli, L; Spampinato, G; Sposato, S; Cozzolino, S; Demarinis, P; Muscato, G

    2016-07-01

    The use of robotics in neurosurgery and, particularly, in stereotactic neurosurgery, is becoming more and more adopted because of the great advantages that it offers. Robotic manipulators easily allow to achieve great precision, reliability, and rapidity in the positioning of surgical instruments or devices in the brain. The aim of this work was to experimentally verify a fully automatic "no hands" surgical procedure. The integration of neuroimaging to data for planning the surgery, followed by application of new specific surgical tools, permitted the realization of a fully automated robotic implantation of leads in brain targets. An anthropomorphic commercial manipulator was utilized. In a preliminary phase, a software to plan surgery was developed, and the surgical tools were tested first during a simulation and then on a skull mock-up. In such a way, several tools were developed and tested, and the basis for an innovative surgical procedure arose. The final experimentation was carried out on anesthetized "large white" pigs. The determination of stereotactic parameters for the correct planning to reach the intended target was performed with the same technique currently employed in human stereotactic neurosurgery, and the robotic system revealed to be reliable and precise in reaching the target. The results of this work strengthen the possibility that a neurosurgeon may be substituted by a machine, and may represent the beginning of a new approach in the current clinical practice. Moreover, this possibility may have a great impact not only on stereotactic functional procedures but also on the entire domain of neurosurgery. PMID:27194228

  3. Numerical simulations of clinical focused ultrasound functional neurosurgery

    PubMed Central

    Pulkkinen, Aki; Werner, Beat; Martin, Ernst; Hynynen, Kullervo

    2014-01-01

    A computational model utilizing grid and finite difference methods was developed to simulate focused ultrasound functional neurosurgery interventions. The model couples the propagation of ultrasound in fluids (soft tissues) and solids (skull) with acoustic and visco-elastic wave equations. The computational model was applied to simulate clinical focused ultrasound functional neurosurgery treatments performed in patients suffering from therapy resistant chronic neuropathic pain. Datasets of five patients were used to derive the treatment geometry. Eight sonications performed in the treatments were then simulated with the developed model. Computations were performed by driving the simulated phased array ultrasound transducer with the acoustic parameters used in the treatments. Resulting focal temperatures and size of the thermal foci were compared quantitatively, in addition to qualitative inspection of the simulated pressure and temperature fields. This study found that the computational model and the simulation parameters predicted an average of 24 ± 13 % lower focal temperature elevations than observed in the treatments. The size of the simulated thermal focus was found to be 40 ± 13 % smaller in the anterior–posterior direction and 22 ± 14% smaller in the inferior–superior direction than in the treatments. The location of the simulated thermal focus was off from the prescribed target by 0.3 ± 0.1 mm, while the peak focal temperature elevation observed in the measurements was off by 1.6 ± 0.6 mm. Although the results of the simulations suggest that there could be some inaccuracies in either the tissue parameters used, or in the simulation methods, the simulations were able to predict the focal spot locations and temperature elevations adequately for initial treatment planning performed to assess, for example, the feasibility of sonication. The accuracy of the simulations could be improved if more precise ultrasound tissue properties (especially of the

  4. Numerical simulations of clinical focused ultrasound functional neurosurgery.

    PubMed

    Pulkkinen, Aki; Werner, Beat; Martin, Ernst; Hynynen, Kullervo

    2014-04-01

    A computational model utilizing grid and finite difference methods were developed to simulate focused ultrasound functional neurosurgery interventions. The model couples the propagation of ultrasound in fluids (soft tissues) and solids (skull) with acoustic and visco-elastic wave equations. The computational model was applied to simulate clinical focused ultrasound functional neurosurgery treatments performed in patients suffering from therapy resistant chronic neuropathic pain. Datasets of five patients were used to derive the treatment geometry. Eight sonications performed in the treatments were then simulated with the developed model. Computations were performed by driving the simulated phased array ultrasound transducer with the acoustic parameters used in the treatments. Resulting focal temperatures and size of the thermal foci were compared quantitatively, in addition to qualitative inspection of the simulated pressure and temperature fields. This study found that the computational model and the simulation parameters predicted an average of 24 ± 13% lower focal temperature elevations than observed in the treatments. The size of the simulated thermal focus was found to be 40 ± 13% smaller in the anterior-posterior direction and 22 ± 14% smaller in the inferior-superior direction than in the treatments. The location of the simulated thermal focus was off from the prescribed target by 0.3 ± 0.1 mm, while the peak focal temperature elevation observed in the measurements was off by 1.6 ± 0.6 mm. Although the results of the simulations suggest that there could be some inaccuracies in either the tissue parameters used, or in the simulation methods, the simulations were able to predict the focal spot locations and temperature elevations adequately for initial treatment planning performed to assess, for example, the feasibility of sonication. The accuracy of the simulations could be improved if more precise ultrasound tissue properties (especially of the

  5. Numerical simulations of clinical focused ultrasound functional neurosurgery

    NASA Astrophysics Data System (ADS)

    Pulkkinen, Aki; Werner, Beat; Martin, Ernst; Hynynen, Kullervo

    2014-04-01

    A computational model utilizing grid and finite difference methods were developed to simulate focused ultrasound functional neurosurgery interventions. The model couples the propagation of ultrasound in fluids (soft tissues) and solids (skull) with acoustic and visco-elastic wave equations. The computational model was applied to simulate clinical focused ultrasound functional neurosurgery treatments performed in patients suffering from therapy resistant chronic neuropathic pain. Datasets of five patients were used to derive the treatment geometry. Eight sonications performed in the treatments were then simulated with the developed model. Computations were performed by driving the simulated phased array ultrasound transducer with the acoustic parameters used in the treatments. Resulting focal temperatures and size of the thermal foci were compared quantitatively, in addition to qualitative inspection of the simulated pressure and temperature fields. This study found that the computational model and the simulation parameters predicted an average of 24 ± 13% lower focal temperature elevations than observed in the treatments. The size of the simulated thermal focus was found to be 40 ± 13% smaller in the anterior-posterior direction and 22 ± 14% smaller in the inferior-superior direction than in the treatments. The location of the simulated thermal focus was off from the prescribed target by 0.3 ± 0.1 mm, while the peak focal temperature elevation observed in the measurements was off by 1.6 ± 0.6 mm. Although the results of the simulations suggest that there could be some inaccuracies in either the tissue parameters used, or in the simulation methods, the simulations were able to predict the focal spot locations and temperature elevations adequately for initial treatment planning performed to assess, for example, the feasibility of sonication. The accuracy of the simulations could be improved if more precise ultrasound tissue properties (especially of the

  6. Transcranial MR-guided High Intensity Focused Ultrasound for Non-Invasive Functional Neurosurgery

    NASA Astrophysics Data System (ADS)

    Werner, Beat; Morel, Anne; Zadicario, Eyal; Jeanmonod, Daniel; Martin, Ernst

    2010-03-01

    While the development of transcranial MR-guided High Intensity Focused Ultrasound has been driven mainly by applications for tumor ablation this new intervention method is also very attractive for functional neurosurgery due to its non-invasiveness, the absence of ionizing radiation and the closed-loop intervention control by MRI. Here we provide preliminary data to demonstrate the clinical feasibility, safety and precision of non-invasive functional neurosurgery by transcranial MR-guided High Intensity Focused Ultrasound.

  7. Executive Function Deficits in Patients after Cerebellar Neurosurgery.

    PubMed

    Mak, Monika; Tyburski, Ernest; Madany, Łukasz; Sokołowski, Andrzej; Samochowiec, Agnieszka

    2016-01-01

    The cerebellum has long been perceived as a structure responsible for the human motor function. According to the contemporary approach, however, it plays a significant role in complex behavior regulatory processes. The aim of this study was to describe executive functions in patients after cerebellar surgery. The study involved 30 patients with cerebellar pathology. The control group comprised 30 neurologically and mentally healthy individuals, matched for sex, age, and number of years of education. Executive functions were measured by the Wisconsin Card Sorting Test (WCST), Stroop Color Word Test (SCWT), Trail Making Test (TMT), and working memory by the Digit Span. Compared to healthy controls, patients made more Errors and Perseverative errors in the WCST, gave more Perseverative responses, and had a lower Number of categories completed. The patients exhibited higher response times in all three parts of the SCWT and TMT A and B. No significant differences between the two groups were reported in their performance of the SCWT and TMT with regard to the measures of absolute or relative interference. The patients had lower score on the backward Digit Span. Patients with cerebellar pathology may exhibit some impairment within problem solving and working memory. Their worse performance on the SCWT and TMT could, in turn, stem from their poor motor-somatosensory control, and not necessarily executive deficits. Our results thus support the hypothesis of the cerebellum's mediating role in the regulation of the activity of the superordinate cognitive control network in the brain. (JINS, 2016, 22, 47-57). PMID:26626541

  8. From Structure to Circuits: The Contribution of MEG Connectivity Studies to Functional Neurosurgery.

    PubMed

    Pang, Elizabeth W; Snead Iii, O C

    2016-01-01

    New advances in structural neuroimaging have revealed the intricate and extensive connections within the brain, data which have informed a number of ambitious projects such as the mapping of the human connectome. Elucidation of the structural connections of the brain, at both the macro and micro levels, promises new perspectives on brain structure and function that could translate into improved outcomes in functional neurosurgery. The understanding of neuronal structural connectivity afforded by these data now offers a vista on the brain, in both healthy and diseased states, that could not be seen with traditional neuroimaging. Concurrent with these developments in structural imaging, a complementary modality called magnetoencephalography (MEG) has been garnering great attention because it too holds promise for being able to shed light on the intricacies of functional brain connectivity. MEG is based upon the elemental principle of physics that an electrical current generates a magnetic field. Hence, MEG uses highly sensitive biomagnetometers to measure extracranial magnetic fields produced by intracellular neuronal currents. Put simply then, MEG is a measure of neurophysiological activity, which captures the magnetic fields generated by synchronized intraneuronal electrical activity. As such, MEG recordings offer exquisite resolution in the time and oscillatory domain and, as well, when co-registered with magnetic resonance imaging (MRI), offer excellent resolution in the spatial domain. Recent advances in MEG computational and graph theoretical methods have led to studies of connectivity in the time-frequency domain. As such, MEG can elucidate a neurophysiological-based functional circuitry that may enhance what is seen with MRI connectivity studies. In particular, MEG may offer additional insight not possible by MRI when used to study complex eloquent function, where the precise timing and coordination of brain areas is critical. This article will review the

  9. From Structure to Circuits: The Contribution of MEG Connectivity Studies to Functional Neurosurgery

    PubMed Central

    Pang, Elizabeth W.; Snead III, O. C.

    2016-01-01

    New advances in structural neuroimaging have revealed the intricate and extensive connections within the brain, data which have informed a number of ambitious projects such as the mapping of the human connectome. Elucidation of the structural connections of the brain, at both the macro and micro levels, promises new perspectives on brain structure and function that could translate into improved outcomes in functional neurosurgery. The understanding of neuronal structural connectivity afforded by these data now offers a vista on the brain, in both healthy and diseased states, that could not be seen with traditional neuroimaging. Concurrent with these developments in structural imaging, a complementary modality called magnetoencephalography (MEG) has been garnering great attention because it too holds promise for being able to shed light on the intricacies of functional brain connectivity. MEG is based upon the elemental principle of physics that an electrical current generates a magnetic field. Hence, MEG uses highly sensitive biomagnetometers to measure extracranial magnetic fields produced by intracellular neuronal currents. Put simply then, MEG is a measure of neurophysiological activity, which captures the magnetic fields generated by synchronized intraneuronal electrical activity. As such, MEG recordings offer exquisite resolution in the time and oscillatory domain and, as well, when co-registered with magnetic resonance imaging (MRI), offer excellent resolution in the spatial domain. Recent advances in MEG computational and graph theoretical methods have led to studies of connectivity in the time-frequency domain. As such, MEG can elucidate a neurophysiological-based functional circuitry that may enhance what is seen with MRI connectivity studies. In particular, MEG may offer additional insight not possible by MRI when used to study complex eloquent function, where the precise timing and coordination of brain areas is critical. This article will review the

  10. Development of computer-aided functions in clinical neurosurgery with PACS

    NASA Astrophysics Data System (ADS)

    Mukasa, Minoru; Aoki, Makoto; Satoh, Minoru; Kowada, Masayoshi; Kikuchi, K.

    1991-07-01

    The introduction of the "Picture Archiving and Communications System (known as PACS)," provides many benefits, including the application of C.A.D., (Computer Aided Diagnosis). Clinically, this allows for the measurement and design of an operation to be easily completed with the CRT monitors of PACS rather than with film, as has been customary in the past. Under the leadership of the Department of Neurosurgery, Akita University School of Medicine, and Southern Tohoku Research Institute for Neuroscience, Koriyama, new computer aided functions with EFPACS (Fuji Electric's PACS) have been developed for use in clinical neurosurgery. This image processing is composed of three parts as follows: (1) Automatic mapping of small lesions depicted on Magnetic Resonance (or MR) images on the brain atlas. (2) Superimposition of two angiographic films onto a single synthesized image. (3) Automatic mapping of the lesion's position (as shown on the. CT images) on the processing image referred to in the foregoing clause 2. The processing in the clause (1) provides a reference for anatomical estimation. The processing in the clause (2) is used for general analysis of the condition of a disease. The processing in the clause (3) is used to design the operation. This image processing is currently being used with good results.

  11. Human pallidothalamic and cerebellothalamic tracts: anatomical basis for functional stereotactic neurosurgery

    PubMed Central

    Gallay, Marc N.; Jeanmonod, Daniel; Liu, Jian

    2008-01-01

    Anatomical knowledge of the structures to be targeted and of the circuitry involved is crucial in stereotactic functional neurosurgery. The present study was undertaken in the context of surgical treatment of motor disorders such as essential tremor (ET) and Parkinson’s disease (PD) to precisely determine the course and three-dimensional stereotactic localisation of the cerebellothalamic and pallidothalamic tracts in the human brain. The course of the fibre tracts to the thalamus was traced in the subthalamic region using multiple staining procedures and their entrance into the thalamus determined according to our atlas of the human thalamus and basal ganglia [Morel (2007) Stereotactic atlas of the human thalamus and basal ganglia. Informa Healthcare Inc., New York]. Stereotactic three-dimensional coordinates were determined by sectioning thalamic and basal ganglia blocks parallel to stereotactic planes and, in two cases, by correlation with magnetic resonance images (MRI) from the same brains prior to sectioning. The major contributions of this study are to provide: (1) evidence that the bulks of the cerebellothalamic and pallidothalamic tracts are clearly separated up to their thalamic entrance, (2) stereotactic maps of the two tracts in the subthalamic region, (3) the possibility to discriminate between different subthalamic fibre tracts on the basis of immunohistochemical stainings, (4) correlations of histologically identified fibre tracts with high-resolution MRI, and (5) evaluation of the interindividual variability of the fibre systems in the subthalamic region. This study should provide an important basis for accurate stereotactic neurosurgical targeting of the subthalamic region in motor disorders such as PD and ET. PMID:18193279

  12. Actualities and Perspectives in Neurosurgery

    PubMed Central

    Iencean, SM; Brehar, FM

    2008-01-01

    In the field of neurosurgery, like in other surgical specialties, the last decades have brought major achievements. The series of revolutionary discoveries has started during the last century in the fifties, with stereotactic radiosurgery, then continued with the implementation of operative microscope (during the seventies), the endovascular embolisation in the nineties and finally with the major improvement in robotic neurosurgery and molecular neurosurgery at the beginning of this century. The major innovation has been brought not only in the field of therapeutical measures but also in the field of neuro– imaging. Thus, the modern MRI with more than 3 Tesla, can reveal to the neurosurgeon the most intimate structures of the nervous system. Several important areas in neurosurgery like: vascular neurosurgery, functional neurosurgery and brain tumors pathology, benefit from the modern technology and from the latest discoveries from genetic and molecular biology. In conclusion, summarizing the discoveries of the last decade, we emphasize that the related areas like genetics, molecular biology, computer technology become more and more important in the future progress of the neurosurgery. PMID:20108475

  13. [In the 100 birth anniversary of the pioneer of stereotactic brain surgery in Poland professor Oskar Liszka. Functional neurosurgery in Poland and in Krakow].

    PubMed

    Stachura, Krzysztof

    2016-01-01

    This article is the report from the meeting of the Medical Society of Cracow, that has been devoted to the 100 birth anniversary of Oskar Liszka, Assoc. Prof., MD. In the course of the meeting Professor Oskar Liszka's figure has been reminded and his work as a pioneer of stereotactic surgery in Poland has been discussed. In the next two sections, the development of functional neurosurgery in Poland and achievements in this field in the Department of Neurosurgery and Neurotraumatology of Jagiellonian University Collegium Medicum in Krakow have been presented. PMID:27197434

  14. Photolasertherapy for the treatment of infections in neurosurgery: experimental and clinical study

    NASA Astrophysics Data System (ADS)

    Lombard, Gian F.

    1996-12-01

    At the first time, the CO2 laser was utilised in infective neurosurgical pathology as a surgical cutting instrument to remove inflammatory pseudomembranes in chronic osteomyelitis, and as a vaporising instmment on the dura mater surface. Successively, the instrument, defocused and at a low power, was used for prolonged and diffuse photo coagulation ofthe surgical cavity, particularly, ofthe dural surface and ofthe osteomyelitic bone edges, with the aim to sterilise tissues. So, we saw a shortening of the average time of wound healing and a lack of recurrence of the septic pathology. Then, we have treated, with CO2 laser, intracranial infective pathology: i.e. primary abscesses, capsulated or not, circumscribed purulent encephalitis, secondary abscesses in surgical cavities (patients operated for intracranial hematomas and tumors). In these cases we have obtained a lack of septic recurrences and an improvement ofneurological post-operative course. Thank to these results, we have continued to use laser in infective pathology; for giving an experimental support to these results we have carried on researches in vivo (on the experimental animal) to see the interaction between the laser and inflammatory tissue, and in vitro (on bacterial culture: in solid and liquid media) to see the laser effect on the bacterial cell. The bacterial cell has been also sensibiized to the photo dynamic effect of the laser (Argon, He-Ne), with hematoporphyrin. The goal of these experiments is to understand the role of thermal, photochemical, and mechanic resonance laser effects in the interaction between laser radiation and bacterial cell.

  15. Neurosurgery at the Catholic University in Rome.

    PubMed

    Rossi, Gian Franco; Colicchio, Gabriella; Di Rocco, Concezio; Maira, Giulio; Meglio, Mario; Scerrati, Massimo

    2002-06-01

    Neurosurgery at the Catholic University in Rome was initiated by Gian Franco Rossi in 1969 and has gradually expanded since then. From the beginning, research has been regarded as an essential part of training and daily activities in the university's neurosurgery programs. The professional and research education of all faculty members includes at least 1 year abroad in a reputable neurosurgical center. Subspecialization is encouraged. Today, the faculty is composed of 3 full professors, 4 associate professors, and 16 assistant professors. The university's neurosurgery programs include the Institute of Neurosurgery, the residency program, and the following clinical units: a Division of General Neurosurgery; three subspecialty sections comprising Neurotraumatology, Pediatric Neurosurgery, and Functional and Spine Surgery; a day hospital; and dedicated laboratories. More than 1700 surgical patients are treated annually. Epilepsy, pain management, parkinsonism, spinal cord and vertebral pathologies, clinical and basic neuro-oncology, cerebrospinal fluid and intracranial pressure dynamics, cerebrovascular disease, neurotrauma, developmental malformations, and peripheral and central nervous system neuroregeneration are the main fields of clinical and research activities. The results of the research performed thus far at the Catholic University in Rome have been reported in more than 900 publications, most of which have appeared in prominent journals and books. Members of the faculty are involved in relevant editorial activities and serve as officers of national and international scientific and professional societies. In 1999, Giulio Maira succeeded Dr. Rossi in directing the Institute of Neurosurgery and the Division of General Neurosurgery. In addition to the history of neurosurgery at the Catholic University in Rome, this article describes present challenges and plans for the future in neurosurgery at the university. PMID:12015854

  16. Functional Neurosurgery in the Human Thalamus by Transcranial Magnetic Resonance Guided Focused Ultrasound

    NASA Astrophysics Data System (ADS)

    Werner, Beat; Morel, Anne; Jeanmonod, Daniel; Martin, Ernst

    2009-04-01

    Potential applications of Transcranial Magnetic Resonance guided Focused Ultrasound (TcMRgFUS) include treatment of functional brain disorders, such as Parkinson's disease, dystonia and tremor, neurogenic pain and tinnitus, neuropsychiatric disorders and epilepsy. In this study we demonstrate the feasibility of non-invasive TcMRgFUS ablation of clinically well established targets in the human thalamus that are currently accessed stereotactically by interventional strategies based on the concept of the thalamocortical dysrhythmia (TCD). Thermal hotspots suitable for clinical intervention were created successfully in anatomical preparations of human ex-vivo heads under pseudo clinical conditions. The hotspots could be positioned at the target locations as needed and local energy deposition was sufficient to create tissue ablation. Numerical simulations based on these experimental data predict that the acoustic energy needed to create ablative lesions in-vivo will be within limits that can safely applied.

  17. Laser applications in neurosurgery

    NASA Astrophysics Data System (ADS)

    Cerullo, Leonard J.

    1985-09-01

    The "false start" of the laser in neurosurgery should not be misconstrued as a denial of the inherent advantages of precision and gentleness in dealing with neural tissue. Rather, early investigators were frustrated by unrealistic expectations, cumbersome equipment, and a general ignorance of microtechnique. By the early 70s, microneurosurgery was well established, surgical laser equipment for free hand and microlinked application had been developed, and a more realistic view of the limitations of the laser had been established. Consequently, the late 70s really heralded the renaissance of the laser in neurosurgery. Since then, there has been an overwhelming acceptance of the tool in a variety of clinical situations, broadly categorized in five groups. 1)|Perhaps the most generally accepted area is in the removal of extra-axial tumors of the brain and spinal cord. These tumors, benign by histology but treacherous by location, do not present until a significant amount of neurological compensation has already occurred. The application of additional trauma to the neural tissue, whether by further tumor growth or surgical manipulation, frequently results in irreversible damage. Here, the ability of the laser to vaporize tissue, in a fairly hemostatic fashion, without mechanical or thermal damage to sensitive surrounding tissues, is essential. 2)|The ability to incise delicate neural tissue with minimal spread of thermal destruction to adjacent functioning tissue makes the laser the ideal instrument when tumors deep under the surface are encountered in the brain or spinal cord. Thus, the second group of applications is in the transgression of normal neural structures to arrive at deeper pathological tissue. 3)|The third area of benefit for the laser in neurosurgery has been in the performance of neuroablative procedures, calling for deliberate destruction of functioning neural tissue in a controlled fashion. Again, the precision and shape confinement of the destructive

  18. Sarcopenia and Neurosurgery

    PubMed Central

    2014-01-01

    Aging process can be characterized as a spontaneous decrease of function in various organs with age. Muscle, as a big organ of human body, undergoes aging process presenting with loss of muscle mass, "sarcopenia". Recently, several working groups have tried to make consensus about sarcopenia for definition and diagnosis. Muscle mass is known to be closely related with bone, brain, fat, cardiovascular and metabolic systems. With increased understanding, clinical and basic researches about sarcopenia have been also increased rapidly from various areas of health science and technology. In this paper, the history and recent concepts of sarcopenia were reviewed and brief discussion of its prospect in the field of neurosurgery was done. PMID:25328642

  19. Computers and neurosurgery.

    PubMed

    Shaikhouni, Ammar; Elder, J Bradley

    2012-11-01

    At the turn of the twentieth century, the only computational device used in neurosurgical procedures was the brain of the surgeon. Today, most neurosurgical procedures rely at least in part on the use of a computer to help perform surgeries accurately and safely. The techniques that revolutionized neurosurgery were mostly developed after the 1950s. Just before that era, the transistor was invented in the late 1940s, and the integrated circuit was invented in the late 1950s. During this time, the first automated, programmable computational machines were introduced. The rapid progress in the field of neurosurgery not only occurred hand in hand with the development of modern computers, but one also can state that modern neurosurgery would not exist without computers. The focus of this article is the impact modern computers have had on the practice of neurosurgery. Neuroimaging, neuronavigation, and neuromodulation are examples of tools in the armamentarium of the modern neurosurgeon that owe each step in their evolution to progress made in computer technology. Advances in computer technology central to innovations in these fields are highlighted, with particular attention to neuroimaging. Developments over the last 10 years in areas of sensors and robotics that promise to transform the practice of neurosurgery further are discussed. Potential impacts of advances in computers related to neurosurgery in developing countries and underserved regions are also discussed. As this article illustrates, the computer, with its underlying and related technologies, is central to advances in neurosurgery over the last half century. PMID:22985531

  20. History of Korean Neurosurgery.

    PubMed

    Hwang, Sung-nam

    2015-08-01

    The year 2012 was the 50th anniversary of the Korean Neurosurgical Society, and in 2013, the 15th World Congress of Neurosurgery took place in Seoul, Korea. Thus, it is an appropriate occasion to introduce the world to the history of the Korean Neurosurgical Society and the foundation, development, and growth of Korean neurosurgery. Historical materials and pictures were collected and reviewed from the history book and photo albums of the Korean Neurosurgical Society. During the last 50 years, the Korean Neurosurgical Society and Korean neurosurgery have developed and grown enormously not only in quantity but also in quality. In every aspect, the turning point from the old to the new era of the Korean Neurosurgical Society and Korean neurosurgery was the year 1980. PMID:25064423

  1. Feasibility of Diffusion Tractography for the Reconstruction of Intra-Thalamic and Cerebello-Thalamic Targets for Functional Neurosurgery: A Multi-Vendor Pilot Study in Four Subjects

    PubMed Central

    Jakab, András; Werner, Beat; Piccirelli, Marco; Kovács, Kázmér; Martin, Ernst; Thornton, John S.; Yousry, Tarek; Szekely, Gabor; O‘Gorman Tuura, Ruth

    2016-01-01

    Functional stereotactic neurosurgery by means of deep brain stimulation or ablation provides an effective treatment for movement disorders, but the outcome of surgical interventions depends on the accuracy by which the target structures are reached. The purpose of this pilot study was to evaluate the feasibility of diffusion tensor imaging (DTI) based probabilistic tractography of deep brain structures that are commonly used for pre- and perioperative targeting for functional neurosurgery. Three targets were reconstructed based on their significance as intervention sites or as a no-go area to avoid adverse side effects: the connections propagating from the thalamus to (1) primary and supplementary motor areas, (2) to somatosensory areas and the cerebello-thalamic tract (CTT). We evaluated the overlap of the reconstructed connectivity based targets with corresponding atlas based data, and tested the inter-subject and inter-scanner variability by acquiring repeated DTI from four volunteers, and on three MRI scanners with similar sequence parameters. Compared to a 3D histological atlas of the human thalamus, moderate overlaps of 35-50% were measured between connectivity- and atlas based volumes, while the minimal distance between the centerpoints of atlas and connectivity targets was 2.5 mm. The variability caused by the MRI scanner was similar to the inter-subject variability, except for connections with the postcentral gyrus where it was higher. While CTT resolved the anatomically correct trajectory of the tract individually, high volumetric variability was found across subjects and between scanners. DTI can be applied in the clinical, preoperative setting to reconstruct the CTT and to localize subdivisions within the lateral thalamus. In our pilot study, such subdivisions moderately matched the borders of the ventrolateral-posteroventral (VLpv) nucleus and the ventral-posterolateral (VPL) nucleus. Limitations of the currently used standard DTI protocols were

  2. Chronic Pain in Neurosurgery.

    PubMed

    Grodofsky, Samuel

    2016-09-01

    This review includes a summary of contemporary theories of pain processing and advocates a multimodal analgesia approach for providing perioperative care. A summary of various medication classes and anesthetic techniques is provided that highlights evidence emerging from neurosurgical literature. This summary covers opioid management, acetaminophen, nonsteroidal antiinflammatories, ketamine, lidocaine, dexmedetomidine, corticosteroids, gabapentin, and regional anesthesia for neurosurgery. At present, there is not enough investigation into these areas to describe best practices for treating or preventing chronic pain in neurosurgery; but providers can identify a wider range of options available to personalize perioperative care strategies. PMID:27521193

  3. Nanotechnology and vascular neurosurgery: an in vivo experimental study on microvessels repair using laser photoactivation of a nanostructured hyaluronan solder.

    PubMed

    Esposito, G; Rossi, F; Matteini, P; Ratto, F; Sabatino, G; Puca, A; Albanese, A; Rossi, G; Marchese, E; Maira, G; Pini, R

    2012-01-01

    Sealing tissues by laser in neurosurgical procedures may overcome problems related to the use of conventional suturing methods which can be associated with various degrees of vascular wall damage. Despite the significant experimental and clinical achievements of the past, a standardized clinical application of laser-welding technology has not yet been implemented. The main problem is related to the use of common organic chromophores. A substantial breakthrough in the laser welding of biological tissues may come from the advent of nanotechnologies. In this paper we describe an experimental study, to confirm the feasibility of an innovative laser-assisted vascular repair (LAVR) technique based on diode laser irradiation and subsequent photoactivation of a hyaluronan solder embedded with near infrared (NIR) absorbing gold nanorods (GNRs), and to analyze the induced closuring effect in a follow-up study performed in animal model. Twenty New Zealand rabbits underwent closure of a 3-mm longitudinal incision performed on the common carotid artery (CCA) by means of 810 nm diode laser irradiation, in conjunction with the topical application of an optimized GNR composite. Effective closure of the arterial wound was accomplished by using very low laser intensity (30 W/cm2). The average CCA occlusion time was as low as 50 sec. Animals underwent different follow-up periods (2, 8, 30 days). After follow-up, they were re-anesthetized, the patency of the treated vessels was tested (Doppler analysis) and then the irradiated vessels were excised and subjected to histological evaluations. Morphological examinations of the samples documented the integrity of the vascular wall. No host reaction to nanoparticles occurred. Collagen and elastic fibers returned to their normal architecture 30 days after treatment. A Scanning Electron Microscopy (SEM) examination and immuno-histochemical analysis demonstrated a full re-endothelization of the vessel walls. We thus confirmed that a laser

  4. NASA Robotic Neurosurgery Testbed

    NASA Technical Reports Server (NTRS)

    Mah, Robert

    1997-01-01

    The detection of tissue interface (e.g., normal tissue, cancer, tumor) has been limited clinically to tactile feedback, temperature monitoring, and the use of a miniature ultrasound probe for tissue differentiation during surgical operations, In neurosurgery, the needle used in the standard stereotactic CT or MRI guided brain biopsy provides no information about the tissue being sampled. The tissue sampled depends entirely upon the accuracy with which the localization provided by the preoperative CT or MRI scan is translated to the intracranial biopsy site. In addition, no information about the tissue being traversed by the needle (e.g., a blood vessel) is provided. Hemorrhage due to the biopsy needle tearing a blood vessel within the brain is the most devastating complication of stereotactic CT/MRI guided brain biopsy. A robotic neurosurgery testbed has been developed at NASA Ames Research Center as a spin-off of technologies from space, aeronautics and medical programs. The invention entitled "Robotic Neurosurgery Leading to Multimodality Devices for Tissue Identification" is nearing a state ready for commercialization. The devices will: 1) improve diagnostic accuracy and precision of general surgery, with near term emphasis on stereotactic brain biopsy, 2) automate tissue identification, with near term emphasis on stereotactic brain biopsy, to permit remote control of the procedure, and 3) reduce morbidity for stereotactic brain biopsy. The commercial impact from this work is the potential development of a whole new generation of smart surgical tools to increase the safety, accuracy and efficiency of surgical procedures. Other potential markets include smart surgical tools for tumor ablation in neurosurgery, general exploratory surgery, prostate cancer surgery, and breast cancer surgery.

  5. NASA Robotic Neurosurgery Testbed

    NASA Technical Reports Server (NTRS)

    Mah, Robert

    1997-01-01

    The detection of tissue interface (e.g., normal tissue, cancer, tumor) has been limited clinically to tactile feedback, temperature monitoring, and the use of a miniature ultrasound probe for tissue differentiation during surgical operations. In neurosurgery, the needle used in the standard stereotactic CT (Computational Tomography) or MRI (Magnetic Resonance Imaging) guided brain biopsy provides no information about the tissue being sampled. The tissue sampled depends entirely upon the accuracy with which the localization provided by the preoperative CT or MRI scan is translated to the intracranial biopsy site. In addition, no information about the tissue being traversed by the needle (e.g., a blood vessel) is provided. Hemorrhage due to the biopsy needle tearing a blood vessel within the brain is the most devastating complication of stereotactic CT/MRI guided brain biopsy. A robotic neurosurgery testbed has been developed at NASA Ames Research Center as a spin-off of technologies from space, aeronautics and medical programs. The invention entitled 'Robotic Neurosurgery Leading to Multimodality Devices for Tissue Identification' is nearing a state ready for commercialization. The devices will: 1) improve diagnostic accuracy and precision of general surgery, with near term emphasis on stereotactic brain biopsy, 2) automate tissue identification, with near term emphasis on stereotactic brain biopsy, to permit remote control of the procedure, and 3) reduce morbidity for stereotactic brain biopsy. The commercial impact from this work is the potential development of a whole new generation of smart surgical tools to increase the safety, accuracy and efficiency of surgical procedures. Other potential markets include smart surgical tools for tumor ablation in neurosurgery, general exploratory surgery, prostate cancer surgery, and breast cancer surgery.

  6. Neurosurgery in Siberia.

    PubMed

    Krivoshapkin, Alexey L; Zelman, Vladimir L

    2012-02-01

    There is archaeological evidence that the first neurosurgical procedure in what is now known as Siberia was performed in 8005 ± 100 B.C. According to signs of bone growth, perhaps more than half of the individuals who received the ancient trepanations survived. In Siberia, the first operations on the human brain and spinal cord were performed in 1909 at Tomsk University Hospital by the outstanding Russian surgeon and professor Vladimir M. Mysh. Professor Mysh initially moved from Saint Petersburg to Tomsk and later to Novosibirsk. Nicolay N. Burdenko, the founder of Russian neurosurgery and the Moscow Neurosurgical Institution, began his medical education at the Tomsk Imperial University. In the 1950s, Professor Ksenia I. Kharitonova exerted her great influence upon the development of neurosurgery in Siberia. Since 1955, and for 30 years thereafter, Professor Kharitonova was recognized as a principal leader of Siberian neurosurgery. She applied every effort to spread neurosurgical knowledge, and she popularized best practices around Siberia and the Far East. Perestroika deconstructed and ultimately eliminated the orderly system of neurosurgical service in the Soviet Union. From another perspective, the process opened the window to the world. Fully equipped centers and clinics with state-of-the-art techniques for neuro-oncology, cerebrovascular diseases, neurotrauma, and spinal pathology management in Novosibirsk, Barnaul, Kemerovo, and Irkutsk were enabled. PMID:22387212

  7. [Prophylactic antibiotics in neurosurgery].

    PubMed

    Iacob, G; Iacob, Simona; Cojocaru, Inimioara

    2007-01-01

    Because of a low risk of infection (around 2-3%), prophylactic use of antibiotics in neurosurgery is a controversial issue. Some neurosurgeons consider that there are strong arguments against the use of antimicrobials (promotion of antibiotic-resistant strains of bacteria, superinfection and adverse drug reactions) and meticulous aseptic techniques could be more usefully than prophylactic antibiotics. On the other hand, despite of being rare, the consequences of a neurosurgical infection can be dramatic and may result in a rapid death, caused by meningitis, cerebritis, abscess formation or sepsis. Clinical studies emphasized that the most important factors influencing the choice of antibiotic prophylaxis in neurosurgery is the patient's immune status, virulence of the pathogens and the type of surgery ("clean contaminated"--procedure that crosses the cranial sinuses, "clean non-implant"--procedure that does not cross the cranial sinuses, CSF shunt surgery, skull fracture). Prophylaxis has become the standard of care for contaminated and clean-contaminated surgery, also for surgery involving insertion of artificial devices. The antibiotic (first/second generation of cephalosporins or vancomycin in allergic patients) should recover only the cutaneous possibly contaminating flora (S. aureus, S. epidermidis) and should be administrated 30' before the surgical incision, intravenously in a single dose. Most studies pointed that identification of the risk factors for infections, correct asepsis and minimal prophylactic antibiotic regimen, help neurosurgeons to improve patient care and to decrease mortality without selecting resistant bacteria. PMID:18293694

  8. Application of lasers in neurosurgery

    SciTech Connect

    Cerullo, L.J. )

    1988-01-01

    This book contains 13 chapters. Some of the titles are: Laser Safety; Photoradiation Therapy of Malignant Brian Tumors; Photochemotherapy: Anesthesiologic Considerations; Power; From Instrument to Tissue; and Theoretical Neurosurgery.

  9. Single Case Study: Neuropsychological Functioning in a Patient Diagnosed with Intermittent Explosive Disorder Pre and Post Neurosurgery.

    PubMed

    Alvarez-Alonso, María José; Morales-Muñoz, Isabel; Castaño-León, Ana María; Lagares, Alfonso; Rubio, Gabriel; Jurado-Barba, Rosa

    2016-01-01

    Intermittent explosive disorder (IED) is characterized by a difficulty to resist the urge to carry out a recognized harmful behavior. The central symptom is aggressiveness, expressed in isolated episodes. Executive function impairments are habitually found in impulse control disorders. Neuropsychology of impulsivity is related to dysfunctions in the orbito-frontal cortex, dorsolateral cortex and anterior-cingulated regions, being consequently involved in cognitive mechanisms of inhibition. Lesions in those areas are common in IED. In the most severe cases of IED, surgical procedures are required for treatment. In this study, we examined JML; a patient suffering from a severe case of IED. He experienced frequent episodes of auto and heteroaggression and multiple psychiatric admissions, and thus stereotactic surgery was the recommended treatment. The procedure consisted of an electrode situated lateral to the lateral ventricle, targeting the projections between frontal and subcortical affected regions. We aimed to study the neuropsychological functioning of JML, before and after electrode implantation. Our results suggested that surgery in IED improves cognitive performance at some levels. JML significantly improved his cognitive flexibility, measured with WCST, and alternate attention assessed with CPT and TMT-B tests, after electrode implantation. Cognitive flexibility deficits may be also related to increased aggressiveness. Therefore, improvements at this level may involve a reduction of impulsivity and aggressive behavior. PMID:27161981

  10. Mythology and Neurosurgery.

    PubMed

    Ökten, Ali İhsan

    2016-06-01

    Myths are the keystone of mythology. They are interpretations of events that have been told as stories and legends for thousands of years, inherited from generation to generation, and have reached the present day. Although most myths are considered figments of the imagination or fictitious legends, all of them contain references to facts from the time they occurred. Mythology, which is a collection of figments of imagination concerning nature and human beings, is a product of human effort to perceive, explain, and interpret the universe and the world, much like science. The interaction between mythology and science dates back to the early days of civilization. Mythology, a reflection of human creativity, is extensively used in modern science, particularly in a terminological context. This article aims to reveal the texture of mythology in neurosurgery, by analyzing the birth of medicine in mythology; heroes such as Apollo and Asklepios, the gods of healing and medicine, as well as Hygieia, the goddess of health and hygiene; and mythological terms and phrases such as Achilles tendon, atlas vertebra, gigantism, priapism syndrome, hippocampus, lethargy, syrinx, and arachnoid. Through the use of symbols, mythology has attempted to explain several subjects, such as human nature, disease, birth, and death. In this respect, mythology and medicine dance arm in arm, and this dance has been going on for centuries. As a result, mythology has manifested itself in many fields within medicine, either anatomically or by giving names to various diseases. PMID:26970479

  11. History of Neurosurgery in Malaysia

    PubMed Central

    RAFFIQ, Azman; ABDULLAH, Jafri Malin; HASPANI, Saffari; ADNAN, Johari Siregar

    2015-01-01

    The development of neurosurgical services and training in Malaysia began in 1963, with the first centre established in its capital city at Hospital Kuala Lumpur, aimed to provide much needed neurosurgical services and training in the field of neurology and neurosurgery. This center subsequently expanded in 1975 with the establishment of the Tunku Abdul Rahman Neuroscience Institute (IKTAR); which integrated the three allied interdependent disciplines of neurosurgery, neurology and psychiatry. The establishment of this institute catalysed the rapid expansion of neurosurgical services in Malaysia and paved the way for development of comprehensive training for doctors, nurses, and paramedics. This culminated in the establishments of a local comprehensive neurosurgery training program for doctors in 2001; followed by a training program for nurses and paramedics in 2006. To date, there are more than 60 neurosurgeons providing expert care in 11 centers across Malaysia, along with trained personnel in the field of neurosciences. PMID:27006632

  12. Progress of women in neurosurgery

    PubMed Central

    Spetzler, Robert F.

    2011-01-01

    Despite advances in issues related to gender equity, barriers to recruiting and retaining women in neurosurgery continue to exist. At the same time, the overall projected shortage of neurosurgeons suggests that women will be vital to the long-term success of the field. Attracting women to neurosurgery can capitalize on strategies, such as mentoring, teaching leadership and negotiating skills, and job sharing or dual training tracks to name a few, that would benefit both men and women passionate about pursuing neurosurgery. Ultimately, personal and institutional accountability must be evaluated to ensure that the best and brightest candidates, regardless of gender, are recruited to neurosurgical programs to promote the health of our challenging but most satisfying profession. PMID:22059098

  13. [New simulation technologies in neurosurgery].

    PubMed

    Byvaltsev, V A; Belykh, E G; Konovalov, N A

    2016-01-01

    The article presents a literature review on the current state of simulation technologies in neurosurgery, a brief description of the basic technology and the classification of simulation models, and examples of simulation models and skills simulators used in neurosurgery. Basic models for the development of physical skills, the spectrum of available computer virtual simulators, and their main characteristics are described. It would be instructive to include microneurosurgical training and a cadaver course of neurosurgical approaches in neurosurgery training programs and to extend the use of three-dimensional imaging. Technologies for producing three-dimensional anatomical models and patient-specific computer simulators as well as improvement of tactile feedback systems and display quality of virtual models are promising areas. Continued professional education necessitates further research for assessing the validity and practical use of simulators and physical models. PMID:27331235

  14. Artificial neural networks in neurosurgery.

    PubMed

    Azimi, Parisa; Mohammadi, Hasan Reza; Benzel, Edward C; Shahzadi, Sohrab; Azhari, Shirzad; Montazeri, Ali

    2015-03-01

    Artificial neural networks (ANNs) effectively analyze non-linear data sets. The aimed was A review of the relevant published articles that focused on the application of ANNs as a tool for assisting clinical decision-making in neurosurgery. A literature review of all full publications in English biomedical journals (1993-2013) was undertaken. The strategy included a combination of key words 'artificial neural networks', 'prognostic', 'brain', 'tumor tracking', 'head', 'tumor', 'spine', 'classification' and 'back pain' in the title and abstract of the manuscripts using the PubMed search engine. The major findings are summarized, with a focus on the application of ANNs for diagnostic and prognostic purposes. Finally, the future of ANNs in neurosurgery is explored. A total of 1093 citations were identified and screened. In all, 57 citations were found to be relevant. Of these, 50 articles were eligible for inclusion in this review. The synthesis of the data showed several applications of ANN in neurosurgery, including: (1) diagnosis and assessment of disease progression in low back pain, brain tumours and primary epilepsy; (2) enhancing clinically relevant information extraction from radiographic images, intracranial pressure processing, low back pain and real-time tumour tracking; (3) outcome prediction in epilepsy, brain metastases, lumbar spinal stenosis, lumbar disc herniation, childhood hydrocephalus, trauma mortality, and the occurrence of symptomatic cerebral vasospasm in patients with aneurysmal subarachnoid haemorrhage; (4) the use in the biomechanical assessments of spinal disease. ANNs can be effectively employed for diagnosis, prognosis and outcome prediction in neurosurgery. PMID:24987050

  15. Computer-aided navigation in neurosurgery.

    PubMed

    Grunert, P; Darabi, K; Espinosa, J; Filippi, R

    2003-05-01

    The article comprises three main parts: a historical review on navigation, the mathematical basics for calculation and the clinical applications of navigation devices. Main historical steps are described from the first idea till the realisation of the frame-based and frameless navigation devices including robots. In particular the idea of robots can be traced back to the Iliad of Homer, the first testimony of European literature over 2500 years ago. In the second part the mathematical calculation of the mapping between the navigation and the image space is demonstrated, including different registration modalities and error estimations. The error of the navigation has to be divided into the technical error of the device calculating its own position in space, the registration error due to inaccuracies in the calculation of the transformation matrix between the navigation and the image space, and the application error caused additionally by anatomical shift of the brain structures during operation. In the third part the main clinical fields of application in modern neurosurgery are demonstrated, such as localisation of small intracranial lesions, skull-base surgery, intracerebral biopsies, intracranial endoscopy, functional neurosurgery and spinal navigation. At the end of the article some possible objections to navigation-aided surgery are discussed. PMID:12962294

  16. The Co-evolution of Neuroimaging and Psychiatric Neurosurgery.

    PubMed

    Dyster, Timothy G; Mikell, Charles B; Sheth, Sameer A

    2016-01-01

    The role of neuroimaging in psychiatric neurosurgery has evolved significantly throughout the field's history. Psychiatric neurosurgery initially developed without the benefit of information provided by modern imaging modalities, and thus lesion targets were selected based on contemporary theories of frontal lobe dysfunction in psychiatric disease. However, by the end of the 20th century, the availability of structural and functional magnetic resonance imaging (fMRI) allowed for the development of mechanistic theories attempting to explain the anatamofunctional basis of these disorders, as well as the efficacy of stereotactic neuromodulatory treatments. Neuroimaging now plays a central and ever-expanding role in the neurosurgical management of psychiatric disorders, by influencing the determination of surgical candidates, allowing individualized surgical targeting and planning, and identifying network-level changes in the brain following surgery. In this review, we aim to describe the coevolution of psychiatric neurosurgery and neuroimaging, including ways in which neuroimaging has proved useful in elucidating the therapeutic mechanisms of neuromodulatory procedures. We focus on ablative over stimulation-based procedures given their historical precedence and the greater opportunity they afford for post-operative re-imaging, but also discuss important contributions from the deep brain stimulation (DBS) literature. We conclude with a discussion of how neuroimaging will transition the field of psychiatric neurosurgery into the era of precision medicine. PMID:27445706

  17. The Co-evolution of Neuroimaging and Psychiatric Neurosurgery

    PubMed Central

    Dyster, Timothy G.; Mikell, Charles B.; Sheth, Sameer A.

    2016-01-01

    The role of neuroimaging in psychiatric neurosurgery has evolved significantly throughout the field’s history. Psychiatric neurosurgery initially developed without the benefit of information provided by modern imaging modalities, and thus lesion targets were selected based on contemporary theories of frontal lobe dysfunction in psychiatric disease. However, by the end of the 20th century, the availability of structural and functional magnetic resonance imaging (fMRI) allowed for the development of mechanistic theories attempting to explain the anatamofunctional basis of these disorders, as well as the efficacy of stereotactic neuromodulatory treatments. Neuroimaging now plays a central and ever-expanding role in the neurosurgical management of psychiatric disorders, by influencing the determination of surgical candidates, allowing individualized surgical targeting and planning, and identifying network-level changes in the brain following surgery. In this review, we aim to describe the coevolution of psychiatric neurosurgery and neuroimaging, including ways in which neuroimaging has proved useful in elucidating the therapeutic mechanisms of neuromodulatory procedures. We focus on ablative over stimulation-based procedures given their historical precedence and the greater opportunity they afford for post-operative re-imaging, but also discuss important contributions from the deep brain stimulation (DBS) literature. We conclude with a discussion of how neuroimaging will transition the field of psychiatric neurosurgery into the era of precision medicine. PMID:27445706

  18. [A short history of endoscopic neurosurgery].

    PubMed

    Wang, Long; Song, Zhi-Bin; Gao, Jian-Wei; Li, Xu-Guangl

    2013-11-01

    Since 1910, rigid cystoscopy was first applied in the lateral ventricular choroid plexus cauterization for the treatment of congenital hydrocephalus, thus, opening up a new window in the endoscopic neurosurgery, but poor surgical outcome and high mortality made the application of endoscopic neurosurgery in question. Latterly, because of the appearance of new microscope and optical fiber endoscope, neuroendoscopy has been applied adequately in neurosurgery, with the increase of its clinical indications. Along with it, the concept of neuroendoscopy in surgery has changed, as well as the expansion of clinical indications. At present, neuroendoscopy technology has become a significant branch of modern neurosurgery. PMID:24524639

  19. Virtual neurosurgery, training for the future.

    PubMed

    Vloeberghs, M; Glover, A; Benford, S; Jones, A; Wang, P; Becker, Adib

    2007-06-01

    Virtual reality (VR) simulators have been created for various surgical specialties. The common theme is extensive use of graphics, confined spaces, limited functionality and limited tactile feedback. A development team at the University of Nottingham, UK, consisting of computer scientists, mechanical engineers, graphic designers and a neurosurgeon, set out to develop a haptic, e.g. tactile simulator for neurosurgery making use of boundary elements (BE). The relative homogeneity of the brain, allows boundary elements, e.g. 'surface only' rendering, to simulate the brain structure. A boundary element simplifies the computing equations saves computing time, by assuming the properties of the surface equal the properties of the body. A limited audit was done by neurosurgical users confirming the potential of the simulator as a training tool. This paper focuses on the application of the computational method and refers to the underlying mathematical structure. Full references are included regarding the mathematical methodology. PMID:17612915

  20. Father of neurosurgery in Hong Kong.

    PubMed

    Tan, Tze-Ching

    2004-04-01

    Neurosurgery in Hong Kong had its origins as a division of General Surgery and became a subspecialty only 46 years ago with the arrival of Hsiang-Lai Wen. For well over a decade, Wen would be the only neurosurgeon in the colony. His contributions to neurosurgery included the ventriculosuperior sagittal sinus shunt and the application of acupuncture in anesthesia, pain ablation, and drug detoxification. A pilot with the China National Aviation Corporation during World War II, he played an active part in the Allied war effort. As a diplomate of the American Board of Neurological Surgery, Wen sought to improve the standard of neurosurgery in Hong Kong and southern China with the establishment of the Hong Kong Neurosurgical Society in 1981 and the Research Institute of Neurosciences in Guangzhou in 1988. Wen was acknowledged as Hong Kong's "father of neurosurgery," and his work paved the way for the development of modern neurosurgery in the region. PMID:15046667

  1. Anaesthesia for elective neurosurgery.

    PubMed

    Dinsmore, J

    2007-07-01

    Neuroanaesthesia continues to develop and expand. It is a speciality where the knowledge and expertise of the anaesthetist can directly influence patient outcome. Evolution of neurosurgical practice is accompanied by new challenges for the anaesthetist. Increasingly, we must think not only as an anaesthetist but also as a neurosurgeon and neurologist. With the focus on functional and minimally invasive procedures, there is an increased emphasis on the provision of optimal operative conditions, preservation of neurocognitive function, minimizing interference with electrophysiological monitoring, and a rapid, high-quality recovery. Small craniotomies, intraoperative imaging, stereotactic interventions, and endoscopic procedures increase surgical precision and minimize trauma to normal tissues. The result should be quicker recovery, minimal perioperative morbidity, and reduced hospital stay. One of the peculiarities of neuroanaesthesia has always been that as much importance is attached to wakening the patient as sending them to sleep. With the increasing popularity of awake craniotomies, there is even more emphasis on this skill. However, despite high-quality anaesthetic research and advances in drugs and monitoring modalities, many controversies remain regarding best clinical practice. This review will discuss some of the current controversies in elective neurosurgical practice, future perspectives, and the place of awake craniotomies in the armamentarium of the neuroanaesthetist. PMID:17573395

  2. Cerebrovascular neurosurgery in evolution: the endovascular paradigm.

    PubMed

    Sorkin, Grant C; Dumont, Travis M; Eller, Jorge L; Mokin, Maxim; Snyder, Kenneth V; Levy, Elad I; Siddiqui, Adnan H; Hopkins, L Nelson

    2014-02-01

    Endovascular technique represents an important, minimally invasive approach to treating cerebrovascular disease. In this article, we discuss the origins of endovascular neurosurgery as a discipline in the context of important technical milestones, evidence-based medicine, and future cerebrovascular neurosurgical training. Cerebrovascular neurosurgery has seen a steady, convergent evolution toward the surgeon capable of seamless incorporation of open and endovascular approaches to any complex vascular disease affecting the central nervous system. Neurosurgery must assume the leadership role in the multidisciplinary neurovascular team. PMID:24402487

  3. Neurosurgery at Fujita Health University, Japan.

    PubMed

    Kanno, T; Kato, Y; Sano, H; Shoda, M; Nonomura, K; Imai, F; Kawase, T; Kanaoka, N; Bannur, U

    2000-06-01

    Neurosurgery at the Fujita Health University began in 1972 with Dr. Tetsuo Kanno. In 1973, he was joined by Dr. Kazuhiro Katada and in the year 1976, an independent neurosurgery department was established with Dr. Kanno as the Chief of Neurosurgery. Under his guidance the department continued to grow and by 1978, a neurosurgical residency program recognised by the Japanese Board of Neurosurgery was established. Integration of laboratory research and clinical experience is the hallmark of this program. The current philosophy is directed towards subspecialization and academic training. This article provides a brief overview of the rapid development of a Neurosurgical Centre to reach international acclaim under the guidance of Prof. Tetsuo Kanno. PMID:10943990

  4. Student-selected components in neurosurgery.

    PubMed

    Clark, David J; Kolias, Angelos G; Garnett, Matthew R; Trivedi, Rikin A; Price, Stephen J; Hutchinson, Peter J

    2016-01-01

    Student-selected components (SSCs) are protected periods of time in the undergraduate medical curriculum which allow students to explore an area of medicine they are interested in. They are particularly valuable in exposing students to smaller specialties like neurosurgery, which are often sparsely covered in the rest of the undergraduate curriculum. Moreover, they provide opportunities for students interested in pursuing a career in neurosurgery to increase their likelihood of being successful in specialty training applications. In this article, we summarise our department's experience of hosting SSCs. Furthermore, we have set out to establish a series of achievable objectives over the course of a typical SSC in neurosurgery. This includes the possibility of participation in research and audit, which, if well planned, can be rewarding for both the student and the host unit. SSCs are an effective means of exposing medical students to neurosurgery and provide a multitude of opportunities for enhancing clinical competencies and career development. PMID:26610147

  5. [Changing the teaching of neurosurgery with information technology].

    PubMed

    Moreau, Jean-Jacques; Caire, François; Kalamarides, Michel; Mireau, Etienne; Dauger, Frédéric; Coignac, Marie-Jo; Charlin, Bernard

    2009-10-01

    A digital campus is a distance learning site that uses the potential of information and communication technologies to disseminate and improve educational services. This website, with open and free access, is built from free software with Web 2.0 technology. It is hosted at the University of Limoges. It functions as a digital library, containing scanned books, slide shows, more than 200 hours of recorded courses and round tables accessible by streaming video. The site is indexed according to the users' needs, by level of knowledge, specialty, keywords, and supplementary MeSH terms. The campus is organized as the College of Neurosurgery (http://college.neurochirurgie.fr). The durability of this type of training (in existence for 9 years now) is made possible by a powerful and committed consortium: the French Society of Neurosurgery, which has created high-quality intellectual and scientific resources, the University of Limoges, the Dupuytren University Hospital Center in Limoges, the region of Limousin, and the French-language Virtual Medical University, which have provided logistic and financial support. To target appropriate levels at various users, we distinguished four groups: medical students, neurosurgery students, neurosurgeons (continuing medical education), and students in allied health fields. All areas of neurosurgery are concerned. All the courses, including tests for self-evaluation and scientific meetings (organized with information and communication technologies) are digitally recorded for the site. The principles that make it possible for a medical discipline to organize around an online project are: a pedagogical conception of projects built in the form of models reusable by other health specialties; a stronghold within professional societies of the relevant specialties able to create high-quality intellectual and scientific resources; an organization by educational levels that can be extended transversally to other health disciplines; and free

  6. Renaissance Neurosurgery: Italy's Iconic Contributions.

    PubMed

    Nanda, Anil; Khan, Imad Saeed; Apuzzo, Michael L

    2016-03-01

    Various changes in the sociopolitical milieu of Italy led to the increasing tolerance of the study of cadavers in the late Middle Ages. The efforts of Mondino de Liuzzi (1276-1326) and Guido da Vigevano (1280-1349) led to an explosion of cadaver-centric studies in centers such as Bologna, Florence, and Padua during the Renaissance period. Legendary scientists from this era, including Leonardo Da Vinci, Andreas Vesalius, Bartolomeo Eustachio, and Costanzo Varolio, furthered the study of neuroanatomy. The various texts produced during this period not only helped increase the understanding of neuroanatomy and neurophysiology but also led to the formalization of medical education. With increased understanding came new techniques to address various neurosurgical problems from skull fractures to severed peripheral nerves. The present study aims to review the major developments in Italy during the vibrant Renaissance period that led to major progress in the field of neurosurgery. PMID:26585723

  7. Intraoperative Image Guidance in Neurosurgery: Development, Current Indications, and Future Trends

    PubMed Central

    Schulz, Chris; Waldeck, Stephan; Mauer, Uwe Max

    2012-01-01

    Introduction. As minimally invasive surgery becomes the standard of care in neurosurgery, it is imperative that surgeons become skilled in the use of image-guided techniques. The development of image-guided neurosurgery represents a substantial improvement in the microsurgical treatment of tumors, vascular malformations, and other intracranial lesions. Objective. There have been numerous advances in neurosurgery which have aided the neurosurgeon to achieve accurate removal of pathological tissue with minimal disruption of surrounding healthy neuronal matter including the development of microsurgical, endoscopic, and endovascular techniques. Neuronavigation systems and intraoperative imaging should improve success in cranial neurosurgery. Additional functional imaging modalities such as PET, SPECT, DTI (for fiber tracking), and fMRI can now be used in order to reduce neurological deficits resulting from surgery; however the positive long-term effect remains questionable for many indications. Method. PubMed database search using the search term “image guided neurosurgery.” More than 1400 articles were published during the last 25 years. The abstracts were scanned for prospective comparative trials. Results and Conclusion. 14 comparative trials are published. To date significant data amount show advantages in intraoperative accuracy influencing the perioperative morbidity and long-term outcome only for cerebral glioma surgery. PMID:22655196

  8. Global Neurosurgery: The Unmet Need.

    PubMed

    Park, Kee B; Johnson, Walter D; Dempsey, Robert J

    2016-04-01

    Globally, the lack of access to basic surgical care causes 3 times as much deaths as HIV/AIDS, tuberculosis, and malaria combined. The magnitude of this unmet need has been described recently, and the numbers are startling. Major shifts in global health agenda have highlighted access to essential and emergency surgery as a high priority. A broad examination of the current global neurosurgical efforts to improve access has revealed some strengths, particularly in the realm of training; however, the demand grossly outstrips the supply; most people in low-income countries do not have access to basic surgical care, either due to lack of availability or affordability. Projects that help create a robust and resilient health system within low- and middle-income countries require urgent implementation. In this context, concurrent scale-up of human resources, investments in capacity building, local data collection, and analysis for accurate assessment are essential. In addition, through process of collaboration and consensus building within the neurosurgical community, a unified voice of neurosurgery is necessary to effectively advocate for all those who need neurosurgical care wherever, whenever. PMID:26732963

  9. Simulation and resident education in spinal neurosurgery

    PubMed Central

    Bohm, Parker E.; Arnold, Paul M.

    2015-01-01

    Background: A host of factors have contributed to the increasing use of simulation in neurosurgical resident education. Although the number of simulation-related publications has increased exponentially over the past two decades, no studies have specifically examined the role of simulation in resident education in spinal neurosurgery. Methods: We performed a structured search of several databases to identify articles detailing the use of simulation in spinal neurosurgery education in an attempt to catalogue potential applications for its use. Results: A brief history of simulation in medicine is given, followed by current trends of spinal simulation utilization in residency programs. General themes from the literature are identified that are integral for implementing simulation into neurosurgical residency curriculum. Finally, various applications are reported. Conclusion: The use of simulation in spinal neurosurgery education is not as ubiquitous in comparison to other neurosurgical subspecialties, but many promising methods of simulation are available for augmenting resident education. PMID:25745588

  10. Comprehensive review on rhino-neurosurgery.

    PubMed

    Hosemann, Werner; Schroeder, Henry W S

    2015-01-01

    In the past 2 decades, an innovative and active field of surgical collaboration has been evolved and established combining the expertise of neurosurgery and rhinosurgery in the endonasal treatment of different lesions affecting the anterior skull base together with the adjacent intranasal and intradural areas. Important prerequisites for this development were improvements of technical devices, definitions of transnasal surgical corridors, and approvements in endonasal reconstructions, e.g. by use of pedicled nasal mucosal flaps. Due to these improvements, the rate of perioperative infectious complications remained acceptable. Interdisciplinary surgical teams (4-hands-2-minds) have been established constituting specialized centers of "rhino-neurosurgery". With growing expertise of these groups, it could be shown that oncological results and perioperative complications were comparable to traditional surgery while at the same time the patients' morbidity could be reduced. The present review encompasses the recent literature focusing on the development, technical details, results, and complications of "rhino-neurosurgery". PMID:26770276

  11. Landmark papers in cerebrovascular neurosurgery 2015.

    PubMed

    Moore, Justin M; Griessenauer, Christoph J; Gupta, Raghav; Adeeb, Nimer; Patel, Apar S; Ogilvy, Christopher S; Thomas, Ajith J

    2016-09-01

    The management of cerebrovascular disease has advanced considerably in 2015. Five randomized control trials have firmly established the role of endovascular thrombectomy for ischemic strokes due to large vessel occlusion. The randomized trial of intraarterial treatment for acute ischemic stroke (MR CLEAN) (Berkhemer et al. NEJM 2015;372:11-20) was the first of a series on the topic. There was a total of 5 randomized controlled trials published showing benefit in terms of functional outcomes at 90days for mechanical thrombectomy including the Endovascular Therapy for Ischemic stroke with perfusion-imaging selection (EXTEND IA) (Campbell et al. NEJM 2015;372:1009-18), the Randomized assessment of rapid endovascular treatment of ischemic stroke (ESCAPE) (Goyal et al. NEJM 2015;372:1019-30) trials, the stent-retriever thrombectomy after IV t-PA is t-PA alone in stroke (SWIFT-PRIME) (Saver et al. NEJM 2015;372:2285-95), and the thrombectomy within 8h after symptom onset in Ischemic stroke (REVASCAT) trial (Jovin et al. NEJM 2015; 372:2296-306). Six-year results from randomized controlled Barrow Ruptured Aneurysm Trial (BRAT) found no significant difference in functional outcomes in patients ruptured aneurysms treated surgically clippings versus endovascular treatment (Spetzler et al. JNS 2015;123:609-17. The 10-year results of the International Subarachnoid Aneurysm trial (ISAT) reported similar mortality rates and good functional outcomes between clipped and coiled patients (Molyneux et al. Lancet 2015;385:691-7). We also discuss the impact of genome wide sequencing studies in familial aneurysms, the largest publication on stent assisted coiling and flow diverter for aneurysms and noteworthy papers relevant to Moyamoya and cavernous malformations (Yang et al. Neurosurgery 2015;77:241-7). PMID:27366977

  12. Reflections on a career in neurosurgery

    PubMed Central

    Heimburger, Robert F.; Heimburger, Douglas C.

    2013-01-01

    Robert Heimburger recounts his career in neurosurgery, including some of the early years of modern neurosurgery and some of the contributions he made, particularly in the areas of early repair of myelomeningocele and spinal cord tethering, high-intensity focused ultrasound for the brain, stereotactic surgery, washing hair and scalps instead of shaving for cranial surgery, and neurosurgical consultation in Asian countries. Now aged 96, he continues to have a keen mind and thorough commitment to the profession that offered him a lifetime of inspiration and service. PMID:23956932

  13. TECHNOLOGICAL INNOVATION IN NEUROSURGERY: A QUANTITATIVE STUDY

    PubMed Central

    Marcus, Hani J; Hughes-Hallett, Archie; Kwasnicki, Richard M; Darzi, Ara; Yang, Guang-Zhong; Nandi, Dipankar

    2015-01-01

    Object Technological innovation within healthcare may be defined as the introduction of a new technology that initiates a change in clinical practice. Neurosurgery is a particularly technologically intensive surgical discipline, and new technologies have preceded many of the major advances in operative neurosurgical technique. The aim of the present study was to quantitatively evaluate technological innovation in neurosurgery using patents and peer-reviewed publications as metrics of technology development and clinical translation respectively. Methods A patent database was searched between 1960 and 2010 using the search terms “neurosurgeon” OR “neurosurgical” OR “neurosurgery”. The top 50 performing patent codes were then grouped into technology clusters. Patent and publication growth curves were then generated for these technology clusters. A top performing technology cluster was then selected as an exemplar for more detailed analysis of individual patents. Results In all, 11,672 patents and 208,203 publications relating to neurosurgery were identified. The top performing technology clusters over the 50 years were: image guidance devices, clinical neurophysiology devices, neuromodulation devices, operating microscopes and endoscopes. Image guidance and neuromodulation devices demonstrated a highly correlated rapid rise in patents and publications, suggesting they are areas of technology expansion. In-depth analysis of neuromodulation patents revealed that the majority of high performing patents were related to Deep Brain Stimulation (DBS). Conclusions Patent and publication data may be used to quantitatively evaluate technological innovation in neurosurgery. PMID:25699414

  14. Neurosurgery, "neurospine," and neuroscience: a vital synergy?

    PubMed

    Nowitzke, Adrian

    2008-10-01

    A fundamental dilemma that faces both neurosurgery in general and the subspecialty field of spine surgery is the question of whether those who trained in the former and now work in the latter should maintain their links with their origins and remain under the broader umbrella of neurosurgery, or whether they should develop their own organizational structure and identity separate from organized neurosurgery. This challenge raises many questions with respect to future potential for growth and development, professional identity, and collegiality. This paper is an edited version of an invited speech to the 2007 Annual Meeting of the Joint Section on Disorders of the Spine and Peripheral Nerves. It uses the concept of synergy to review relevant history and explore possible future options for neurosurgery, neurospine, and neuroscience. An example from medical politics is used to illustrate the importance of perspective in approaching these questions, and examples of current therapeutic cutting-edge endeavors highlight the need for team-based behavior that takes a broad view. The premise of the paper is that while individual and specialty aspirations need to be acknowledged, considered, and managed, the results from truly working together will be greater than the sum of the individual efforts-synergy. PMID:18939916

  15. Experimental measurement of the Melnikov function

    NASA Astrophysics Data System (ADS)

    Meunier, Patrice; Huck, Peter; Nobili, Clément; Villermaux, Emmanuel

    2015-07-01

    We study the transport properties of a genuine two-dimensional flow with a large mean velocity perturbed periodically in time by means of an original experimental technique. The flow generated by the co-rotation of two cylinders is both stratified with a linear density gradient using salted water and viscous in order to prevent Ekman pumping and centrifugal instabilities. Thus, the mean flow contains a hyperbolic point with a homoclinic streamline, which we perturb periodically by an extra oscillation. A blob of scalar injected close to the stagnation point contracts on the stable manifold and stretches in the unstable direction. The distance between the stable and the unstable manifolds is measured as the distance between the maximum and the minimum of the dye undulating pattern and is recorded as a function of the perturbation frequency. This distance, also called the Melnikov function, presents a maximum when the residence time of a fluid particle in the mean flow is about half a perturbation period. This resonance criterion is recovered with good quantitative agreement by the theoretical prediction of the Melnikov function computed for this flow.

  16. Susceptibility artefact correction using dynamic graph cuts: application to neurosurgery.

    PubMed

    Daga, Pankaj; Pendse, Tejas; Modat, Marc; White, Mark; Mancini, Laura; Winston, Gavin P; McEvoy, Andrew W; Thornton, John; Yousry, Tarek; Drobnjak, Ivana; Duncan, John S; Ourselin, Sebastien

    2014-10-01

    Echo Planar Imaging (EPI) is routinely used in diffusion and functional MR imaging due to its rapid acquisition time. However, the long readout period makes it prone to susceptibility artefacts which results in geometric and intensity distortions of the acquired image. The use of these distorted images for neuronavigation hampers the effectiveness of image-guided surgery systems as critical white matter tracts and functionally eloquent brain areas cannot be accurately localised. In this paper, we present a novel method for correction of distortions arising from susceptibility artefacts in EPI images. The proposed method combines fieldmap and image registration based correction techniques in a unified framework. A phase unwrapping algorithm is presented that can efficiently compute the B0 magnetic field inhomogeneity map as well as the uncertainty associated with the estimated solution through the use of dynamic graph cuts. This information is fed to a subsequent image registration step to further refine the results in areas with high uncertainty. This work has been integrated into the surgical workflow at the National Hospital for Neurology and Neurosurgery and its effectiveness in correcting for geometric distortions due to susceptibility artefacts is demonstrated on EPI images acquired with an interventional MRI scanner during neurosurgery. PMID:25047865

  17. Neuromuscular Functions on Experimental Acute Methanol Intoxication

    PubMed Central

    Moral, Ali Reşat; Çankayalı, İlkin; Sergin, Demet; Boyacılar, Özden

    2015-01-01

    Objective The incidence of accidental or suicidal ingestion of methyl alcohol is high and methyl alcohol intoxication has high mortality. Methyl alcohol intoxication causes severe neurological sequelae and appears to be a significant problem. Methyl alcohol causes acute metabolic acidosis, optic neuropathy leading to permanent blindness, respiratory failure, circulatory failure and death. It is metabolised in the liver, and its metabolite formic acid has direct toxic effects, causing oxidative stress, mitochondrial damage and increased lipid peroxidation associated with the mechanism of neurotoxicity. Methanol is known to cause acute toxicity of the central nervous system; however, the effects on peripheral neuromuscular transmission are unknown. In our study, we aimed to investigate the electrophysiological effects of experimentally induced acute methanol intoxication on neuromuscular transmission in the early period (first 24 h). Methods After approval by the Animal Experiment Ethics Committee of Ege University, the study was carried out on 10 Wistar rats, each weighing about 200 g. During electrophysiological recordings and orogastric tube insertion, the rats were anaesthetised using intra-peritoneal (IP) injection of ketamine 100 mg kg−1 and IP injection of xylazine 10 mg kg−1. The rats were given 3 g kg−1 methyl alcohol by the orogastric tube. Electrophysiological measurements from the gastrocnemius muscle were compared with baseline. Results Latency measurements before and 24 h after methanol injection were 0.81±0.11 ms and 0.76±0.12 ms, respectively. CMAP amplitude measurements before and 24 h after methanol injection were 9.85±0.98 mV and 9.99±0.40 mV, respectively. CMAP duration measurements before and 24 h after methanol injection were 9.86±0.03 ms and 9.86±0.045 ms, respectively. Conclusion It was concluded that experimental methanol intoxication in the acute phase (first 24 h) did not affect neuromuscular function. PMID:27366524

  18. The history of neurosurgery in Bolivia and pediatric neurosurgery in Santa Cruz de la Sierra

    PubMed Central

    Dabdoub, Carlos F.; Dabdoub, Carlos B.

    2013-01-01

    The practice of neurosurgery in Bolivia began thousands of years ago with skull trepanation. This procedure dates from the earliest period of the Tiwanaku culture, a preInca civilization. Neurosurgical development in Bolivia has its origins in the late 19th century and can be divided in two stages. At the beginning, before the advent of neurosurgery as a discipline, some general surgeons performed procedures on the skull and brain. Formal neurosurgery in Bolivia was developed with the arrival of neurosurgeons trained in the United States and some countries of South America. The Bolivian Neurosurgical Society was created in 1975. Nowadays, our national society has 74 members. It is affiliated with the World Federation of Neurosurgical Societies and the Latin American Federation of Neurosurgical Societies. Presently, neurosurgery in Bolivia is similar to that seen in developed countries. In this sense, government programs should dedicate more financial support to establish specialized healthcare centers where the management of complex central nervous system lesions could be offered. In contrast, we believe that encouraging the local training of young neurosurgeons is one of the most important factors in the development of neurosurgery in Bolivia or any other country. PMID:24232440

  19. Advances in neurosurgery: The Fujita Health University experience

    PubMed Central

    Kumar, Ashish

    2011-01-01

    In a world with rapidly changing technologies in the field of neurosurgery, Japan leads the world in many subspecialities like vascular neurosurgery. Apart from this, neuro-oncology and spinal surgeries are also among the premium quality operations performed in the region. I would like to share my experience of spending 3 months at the Fujita Health University, Nagoya, Japan, and the rich expertise and technologies encountered during the period, which made me understand Neurosurgery in a better way. PMID:22059102

  20. Laser Nano-Neurosurgery from Gentle Manipulation to Nano-Incision of Neuronal Cells and Scaffolds: An Advanced Neurotechnology Tool.

    PubMed

    Soloperto, Alessandro; Palazzolo, Gemma; Tsushima, Hanako; Chieregatti, Evelina; Vassalli, Massimo; Difato, Francesco

    2016-01-01

    Current optical approaches are progressing far beyond the scope of monitoring the structure and function of living matter, and they are becoming widely recognized as extremely precise, minimally-invasive, contact-free handling tools. Laser manipulation of living tissues, single cells, or even single-molecules is becoming a well-established methodology, thus founding the onset of new experimental paradigms and research fields. Indeed, a tightly focused pulsed laser source permits complex tasks such as developing engineered bioscaffolds, applying calibrated forces, transfecting, stimulating, or even ablating single cells with subcellular precision, and operating intracellular surgical protocols at the level of single organelles. In the present review, we report the state of the art of laser manipulation in neuroscience, to inspire future applications of light-assisted tools in nano-neurosurgery. PMID:27013962

  1. Laser Nano-Neurosurgery from Gentle Manipulation to Nano-Incision of Neuronal Cells and Scaffolds: An Advanced Neurotechnology Tool

    PubMed Central

    Soloperto, Alessandro; Palazzolo, Gemma; Tsushima, Hanako; Chieregatti, Evelina; Vassalli, Massimo; Difato, Francesco

    2016-01-01

    Current optical approaches are progressing far beyond the scope of monitoring the structure and function of living matter, and they are becoming widely recognized as extremely precise, minimally-invasive, contact-free handling tools. Laser manipulation of living tissues, single cells, or even single-molecules is becoming a well-established methodology, thus founding the onset of new experimental paradigms and research fields. Indeed, a tightly focused pulsed laser source permits complex tasks such as developing engineered bioscaffolds, applying calibrated forces, transfecting, stimulating, or even ablating single cells with subcellular precision, and operating intracellular surgical protocols at the level of single organelles. In the present review, we report the state of the art of laser manipulation in neuroscience, to inspire future applications of light-assisted tools in nano-neurosurgery. PMID:27013962

  2. Walter E. Dandy's contributions to vascular neurosurgery.

    PubMed

    Kretzer, Ryan M; Coon, Alexander L; Tamargo, Rafael J

    2010-06-01

    Although Walter E. Dandy (1886-1946) is appropriately credited with the first surgical clipping of an intracranial aneurysm in 1937--a procedure that established the modern field of vascular neurosurgery--his numerous other contributions to this specialty are not as well known. Dandy can be credited with the first detailed description of the vein of Galen malformation, the first description of x-ray visualization of an intracranial aneurysm, the first characterization of basilar artery dolichoectasia, and the publication of the first comprehensive operative case series of arteriovenous malformations, cavernous malformations, and developmental venous anomalies. In addition, Dandy performed the first surgical trapping of a cavernous internal carotid artery (ICA) aneurysm by clipping the supraclinoid ICA and ligating the cervical ICA, and he also executed the first intracranial surgical clipping of the ICA to treat a carotid-cavernous fistula. In this article the authors describe Dandy's contributions to the field of vascular neurosurgery. PMID:20515365

  3. Photodynamic application in neurosurgery: present and future

    NASA Astrophysics Data System (ADS)

    Kostron, Herwig

    2009-06-01

    Photodynamic techniques such as photodynamic diagnosis (PDD), fluorescence guided tumor resection (FGR) and photodynamic therapy (PDT) are currently undergoing intensive clinical investigations as adjunctive treatment for malignant brain tumours. This review provides an overview on the current clinical data and trials as well as on photosensitisers, technical developments and indications for photodynamic application in Neurosurgery. Furthermore new developments and clinical significance of FGR for neurosurgery will be discussed. Over 1000 patients were enrolled in various clinical phase I/II trials for PDT for malignant brain tumours. Despite various treatment protocols, variation of photosensitisers and light dose there is a clear trend towards prolonging median survival after one single PDT as compared to conventional therapeutic modalities. The median survival after PDT for primary glioblastoma multiforme WHO IV was 19 months and for recurrent GBM 9 months as compared to standard convential treatment which is 15 months and 3 months, respectively. FGR in combination with adjunctive radiation was significantly superior to standard surgical resection followed by radiation. The combination of FGR/PDD and intraoperative PDT increased significantly survival in recurrent glioblastoma patients. The combination of PDD/ FGR and PDT offers an exciting approach to the treatment of malignant brain tumours "to see and to treat." PDT was generally well tolerated and side effects consisted of occasionally increased intracranial pressure and prolonged skin sensitivity against direct sunlight. This review covers the current available data and draws the future potential of PDD and PDT for its application in neurosurgery.

  4. [The origins of the French neurosurgery].

    PubMed

    Brunon, J

    2016-06-01

    Modern French neurosurgery starts at the beginning of the XXth century under the motivation of Joseph Babinski. He submitted his patients to Thierry de Martel who had learned this new specialized area of medicine with H. Cushing in the États-Unis and V. Horsey in Great Britain. His first successfully treated case of an intracranial tumor was published in 1909. But the true founding father was Clovis Vincent, initially a neurologist and collaborator of de Martel, who became the first chairman in 1933 of the neurosurgical department at the Pitié hospital of Paris and the first professor of neurosurgery in 1938. After the Second World War, many departments were created outside of Paris. Neurosurgery was definitively recognized as a specialized area in medicine in 1948. Currently, more than 400 neurosurgeons work in France. Because I had the very great privilege to be present at the birth of this society in 1970 and to still be in contact with some of the second and third generation of French neurosurgeons who led it to its high international recognition, the Chairman of the French Neurosurgical Society asked me to write this short historical vignette. PMID:27234912

  5. Neurosurgery: A profession or a technical trade?

    PubMed Central

    Watts, Clark

    2014-01-01

    The American Association of Neurological Surgeons (AANS), 11 years ago converted its Internal Revenue Code (IRC) tax status from a 501 (c) (3) to a 501 (c) (6) entity. By doing so, the professional medical association, now a trade association, was able to more aggressively lobby, support political campaigns, and pursue business opportunities for its members. In the following decade, major changes were seen in the practice of neurosurgery, especially as it relates to spine surgery. With the majority of neurosurgeons limiting themselves to a spine practice, an increased number of spinal procedures, most noted in the Medicare population, was recorded. For example, a 15-fold increase in complex spinal fusions for spinal stenosis was seen between 2002 and 2007. While the basis for this increase was not readily apparent, it was associated with a reduction in reimbursement per case of about 50%, fueling the belief that the increase in complexity of surgery permitted recovery of fees in complex cases to off-set the loss of reimbursement for simpler cases. Considering the growth of spinal surgery within neurosurgery, and decrease funding for spine surgery, in the future there may be too many surgeons chasing too few dollars. There appears to be within neurosurgery a crisis developing where future manpower projections do not realistically match future anticipated specialty funding. PMID:25558426

  6. Graph theory analysis of complex brain networks: new concepts in brain mapping applied to neurosurgery.

    PubMed

    Hart, Michael G; Ypma, Rolf J F; Romero-Garcia, Rafael; Price, Stephen J; Suckling, John

    2016-06-01

    Neuroanatomy has entered a new era, culminating in the search for the connectome, otherwise known as the brain's wiring diagram. While this approach has led to landmark discoveries in neuroscience, potential neurosurgical applications and collaborations have been lagging. In this article, the authors describe the ideas and concepts behind the connectome and its analysis with graph theory. Following this they then describe how to form a connectome using resting state functional MRI data as an example. Next they highlight selected insights into healthy brain function that have been derived from connectome analysis and illustrate how studies into normal development, cognitive function, and the effects of synthetic lesioning can be relevant to neurosurgery. Finally, they provide a précis of early applications of the connectome and related techniques to traumatic brain injury, functional neurosurgery, and neurooncology. PMID:26544769

  7. Application of Predictive Nursing Reduces Psychiatric Complications in ICU Patients after Neurosurgery

    PubMed Central

    LIU, Qiong; ZHU, Hui

    2016-01-01

    Background: Our aim was to investigate the effects of clinical application of perioperative predictive nursing on reducing psychiatric complications in Intensive Care Unit (ICU) patients after neurosurgery. Methods: A total of 129 patients who underwent neurosurgery and received intensive care were enrolled in our study from February 2013 to February 2014. These patients were divided into two groups: the experimental group (n=68) receiving predictive nursing before and after operation, and the control group (n=61) with general nursing. Clinical data including length of ICU stay, duration of the patients’ psychiatric symptoms, form and incidence of adverse events, and patient satisfaction ratings were recorded, and their differences between the two groups were analyzed. Results: The duration of psychiatric symptoms and the length of ICU stay for patients in the experimental group were significantly shorter than those in the control group (P<0.05). The incidence of adverse events and psychiatric symptoms, such as sensory and intuition disturbance, thought disturbance, emotional disorder, and consciousness disorder, in the experimental group was significantly lower than that in the control group (P<0.05). Patient satisfaction ratings were significantly higher in the experimental group than those in the control group (P<0.05). Conclusion: Application of predictive nursing on ICU patients who undergo neurosurgery could effectively reduce the incidence of psychiatric symptoms as well as other adverse events. Our study provided clinical evidences to encourage predictive nursing in routine settings for patients in critical conditions. PMID:27252916

  8. 21 CFR 882.4800 - Self-retaining retractor for neurosurgery.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Self-retaining retractor for neurosurgery. 882...-retaining retractor for neurosurgery. (a) Identification. A self-retaining retractor for neurosurgery is a self-locking device used to hold the edges of a wound open during neurosurgery. (b)...

  9. 21 CFR 882.4800 - Self-retaining retractor for neurosurgery.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Self-retaining retractor for neurosurgery. 882...-retaining retractor for neurosurgery. (a) Identification. A self-retaining retractor for neurosurgery is a self-locking device used to hold the edges of a wound open during neurosurgery. (b)...

  10. 21 CFR 882.4800 - Self-retaining retractor for neurosurgery.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Self-retaining retractor for neurosurgery. 882...-retaining retractor for neurosurgery. (a) Identification. A self-retaining retractor for neurosurgery is a self-locking device used to hold the edges of a wound open during neurosurgery. (b)...

  11. 21 CFR 882.4800 - Self-retaining retractor for neurosurgery.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Self-retaining retractor for neurosurgery. 882...-retaining retractor for neurosurgery. (a) Identification. A self-retaining retractor for neurosurgery is a self-locking device used to hold the edges of a wound open during neurosurgery. (b)...

  12. 21 CFR 882.4800 - Self-retaining retractor for neurosurgery.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Self-retaining retractor for neurosurgery. 882...-retaining retractor for neurosurgery. (a) Identification. A self-retaining retractor for neurosurgery is a self-locking device used to hold the edges of a wound open during neurosurgery. (b)...

  13. Smartphone use in neurosurgery? APP-solutely!

    PubMed Central

    Zaki, Michael; Drazin, Doniel

    2014-01-01

    Background: A number of smartphone medical apps have recently emerged that may be helpful for the neurosurgical patient, practitioner, and trainee. This study aims to review the current neurosurgery-focused apps available for the iPhone, iPad, and Android platforms as of December 2013. Methods: Two of the most popular smartphone app stores (Apple Store and Android Google Play Store) were surveyed for neurosurgery-focused apps in December 2013. Search results were categorized based on their description page. Data were collected on price, rating, app release date, target audience, and medical professional involvement in app design. A review of the top apps in each category was performed. Results: The search resulted in 111 unique apps, divided into these 7 categories: 16 (14%) clinical tools, 17 (15%) conference adjunct, 27 (24%) education, 18 (16%) literature, 15 (14%) marketing, 10 (9%) patient information, and 8 (7%) reference. The average cost of paid apps was $23.06 (range: $0.99-89.99). Out of the 111 apps, 71 (64%) were free, 48 (43%) had reviews, and 14 (13%) had more than 10 reviews. Seventy-three (66%) apps showed evidence of medical professional involvement. The number of apps being released every year has been increasing since 2009. Conclusions: There are a number of neurosurgery-themed apps available to all audiences. There was a lack of patient information apps for nonspinal procedures. Most apps did not have enough reviews to evaluate their quality. There was also a lack of oversight to validate the accuracy of medical information provided in these apps. PMID:25101208

  14. Development and Evaluation of a Registration Methodology for Information-Guided Precision Robotic Laser Neurosurgery System

    NASA Astrophysics Data System (ADS)

    Nakamura, Ryoichi; Hara, Mikiko; Omori, Shigeru; Uematsu, Miyuki; Umezu, Mitsuo; Muragaki, Yoshihiro; Iseki, Hiroshi

    To establish safe, precise, and minimally invasive surgery, Computer Aided Surgery (CAS) systems, such as intra-operative imaging and navigation system to detect the location of the target of therapy, and surgical robot system, are very powerful tools. There is strong need to combine these CAS systems for fusion of advanced diagnosis and treatment technologies. In this paper, we introduce our new method to register the intraoperative imaging information, robotic surgery system, and patient using surgical navigation system. Using our Open-MRI navigation system and laser surgery system for neurosurgery, we can make registration between these system and patient precisely. The experimental result shows that the error on the registration between image data and the laser surgery system is low enough to fulfill the requirement of laser surgery system in the use of high-resolution image data. This system realizes the safe, precise and minimally invasive neurosurgery by the combination of intra-operative diagnosis and advanced therapeutic device.

  15. Mythological and Prehistorical Origins of Neurosurgery.

    PubMed

    Nanda, Anil; Filis, Andreas; Kalakoti, Piyush

    2016-05-01

    Mythology has a cultural appeal, and the description of some neurosurgical procedures in the Hindu, Greek, Egyptian, and Chinese mythology has a bearing to the origins of our professions. The traces to some of our modern-day practices also can be linked back to the ancient prehistoric eras of the Siberian, Persian, and the Andean region. In this historical perspective, we briefly dwell into individual accounts through the prism of different cultures to highlight the development of neurosurgery in mythology and prehistoric era. PMID:26947728

  16. Cost-effectiveness research in neurosurgery.

    PubMed

    Zygourakis, Corinna C; Kahn, James G

    2015-04-01

    Cost and value are increasingly important components of health care discussions. Despite a plethora of cost and cost-effectiveness analyses in many areas of medicine, there has been little of this type of research for neurosurgical procedures. This scarcity is vexing because this specialty represents one of the most expensive areas in medicine. This article discusses the general principles of cost-effectiveness analyses and reviews the cost- and cost-effectiveness-related research to date in neurosurgical subspecialties. The need for standardization of cost and cost-effectiveness measurement and reporting within neurosurgery is highlighted and a set of metrics for this purpose is defined. PMID:25771274

  17. Neurosurgery for mental disorders: a review.

    PubMed

    Heeramun-Aubeeluck, A; Lu, Z

    2013-05-01

    Neurosurgical interventions date back to ancient civilization, 5100 BC through a practice known as trephination. Due to past abuse and ethical considerations, neurosurgical interventions in psychiatry remain a controversial issue. This article aims to review the different surgical techniques and their current application in the treatment of psychiatric disorders. The U.S Food and Drug Administration (FDA) gave its approval for vagal nerve stimulation (VNS) for the management of treatment-resistant depression in 2005 and deep brain stimulation (DBS) for refractory obsessive-compulsive disorders (OCD) in 2009. These invasive but non destructive techniques represent the future of neurosurgery for mental disorder. PMID:23739819

  18. The functions of language: an experimental study.

    PubMed

    Redhead, Gina; Dunbar, R I M

    2013-01-01

    We test between four separate hypotheses (social gossip, social contracts, mate advertising and factual information exchange) for the function(s) of language using a recall paradigm. Subjects recalled the social content of stories (irrespective of whether this concerned social behavior, defection or romantic events) significantly better than they did ecological information. Recall rates were no better on ecological stories if they involved flamboyant language, suggesting that, if true, Miller's "Scheherazade effect" may not be independent of content. One interpretation of these results might be that language evolved as an all-purpose social tool, and perhaps acquired specialist functions (sexual advertising, contract formation, information exchange) at a later date through conventional evolutionary windows of opportunity. PMID:23945312

  19. First experimental measurement of the Melnikov function

    NASA Astrophysics Data System (ADS)

    Meunier, Patrice; Huck, Peter; Villermaux, Emmanuel

    2014-11-01

    The problem of scalar mixing in a 2D flow has been extensively studied numerically by following Lagrangian tracers or theoretically using the tools of dynamical systems (KAM tori, quasi-periodic orbits, chaotic attractors...). However, in all these modelisations, the diffusion of the scalar is usually neglected for the purposes of the numerical/theoretical tools. We present here an experiment with an exactly 2D flow, which allows to study properly the diffusive and mixing problem at very large Peclet number. To avoid any 3D flow, the fluid is stratified with a linear density gradient using salted water. Moreover, the viscosity of the water is decreased of an order of magnitude by adding 10% ucon oil in the water. The flow under study is created by the co-rotation of two vertical cylinders, leading to a homoclinc point at the center. This base flow is perturbed periodically by a third oscillating cylinder. The dye injected at the center settles on the stable manifold of the homoclinic point. The distance between the stable and the unstable manifold is measured as half the distance between the maximum and the minimum of the dye's undulation. The results are in good quantitative agreement with the theoretical prediction of the Melnikov function for this flow.

  20. The 2015 AANS Presidential Address: Neurosurgery's founding principles.

    PubMed

    Harbaugh, Robert E

    2015-12-01

    These are turbulent times for American neurosurgery. It is important to look ahead and prepare for the future but it is also important to look back-for it is memory and tradition that prevent the tyranny of the present. It is impossible to know where we are going if we don't remember where we were. In this paper I want to discuss the founding principles of neurosurgery-the principles that have allowed neurosurgery to prosper in its first century-and to stress the importance of adhering to these principles in times of change. I also want to talk to you about how the American Association of Neurological Surgeons (AANS) is helping neurosurgeons honor our founding principles, while preparing neurosurgery for its second century. PMID:26620322

  1. Bulgarian military neurosurgery: from Warsaw Pact to the North Atlantic Treaty Organization.

    PubMed

    Enchev, Yavor; Eftimov, Tihomir

    2010-05-01

    After 45 years as a closest ally of the Soviet Union in the Warsaw Pact, founded mainly against the US and the Western Europe countries, and 15 years of democratic changes, since 2004 Bulgaria has been a full member of NATO and an equal and trusted partner of its former enemies. The unprecedented transformation has affected all aspects of the Bulgarian society. As a function of the Bulgarian Armed Forces, Bulgarian military medicine and in particular Bulgarian military neurosurgery is indivisibly connected with their development. The history of Bulgarian military neurosurgery is the history of the transition from the Union of Soviet Socialist Republics military system and military medicine to NATO standards in every aspect. The career of the military neurosurgeon in Bulgaria is in many ways similar to that of the civilian neurosurgeon, but there are also many peculiarities. The purpose of this study was to outline the background and the history of Bulgarian military neurosurgery as well as its future trends in the conditions of world globalization. PMID:20568931

  2. Aura of technology and the cutting edge: a history of lasers in neurosurgery.

    PubMed

    Ryan, Robert W; Spetzler, Robert F; Preul, Mark C

    2009-09-01

    In this historical review the authors examine the important developments that have led to the availability of laser energy to neurosurgeons as a unique and sometimes invaluable tool. They review the physical science behind the function of lasers, as well as how and when various lasers based on different lasing mediums were discovered. They also follow the close association between advances in laser technology and their application in biomedicine, from early laboratory experiments to the first clinical experiences. Because opinions on the appropriate role of lasers in neurosurgery vary widely, the historical basis for some of these views is explored. Initial enthusiasm for a technology that appears to have innate advantages for safe resections has often given way to the strict limitations and demands of the neurosurgical operating theater. However, numerous creative solutions to improve laser delivery, power, safety, and ergonomics demonstrate the important role that technological advances in related scientific fields continue to offer neurosurgery. Benefiting from the most recent developments in materials science, current CO(2) laser delivery systems provide a useful addition to the neurosurgical armamentarium when applied in the correct circumstances and reflect the important historical advances that come about from the interplay between neurosurgery and technology. PMID:19722821

  3. Recent Trends in Conducting School-Based Experimental Functional Analyses

    ERIC Educational Resources Information Center

    Carter, Stacy L.

    2009-01-01

    Demonstrations of school-based experimental functional analyses have received limited attention within the literature. School settings present unique practical and ethical concerns related to the implementation of experimental analyses which were originally developed within clinical settings. Recent examples have made definite contributions toward…

  4. Comprehensive review on rhino-neurosurgery

    PubMed Central

    Hosemann, Werner; Schroeder, Henry W.S.

    2015-01-01

    In the past 2 decades, an innovative and active field of surgical collaboration has been evolved and established combining the expertise of neurosurgery and rhinosurgery in the endonasal treatment of different lesions affecting the anterior skull base together with the adjacent intranasal and intradural areas. Important prerequisites for this development were improvements of technical devices, definitions of transnasal surgical corridors, and approvements in endonasal reconstructions, e.g. by use of pedicled nasal mucosal flaps. Due to these improvements, the rate of perioperative infectious complications remained acceptable. Interdisciplinary surgical teams (4-hands-2-minds) have been established constituting specialized centers of “rhino-neurosurgery”. With growing expertise of these groups, it could be shown that oncological results and perioperative complications were comparable to traditional surgery while at the same time the patients’ morbidity could be reduced. The present review encompasses the recent literature focusing on the development, technical details, results, and complications of “rhino-neurosurgery”. PMID:26770276

  5. Options for perioperative pain management in neurosurgery

    PubMed Central

    Vadivelu, Nalini; Kai, Alice M; Tran, Daniel; Kodumudi, Gopal; Legler, Aron; Ayrian, Eugenia

    2016-01-01

    Moderate-to-severe pain following neurosurgery is common but often does not get attention and is therefore underdiagnosed and undertreated. Compounding this problem is the traditional belief that neurosurgical pain is inconsequential and even dangerous to treat. Concerns about problematic effects associated with opioid analgesics such as nausea, vomiting, oversedation, and increased intracranial pressure secondary to elevated carbon dioxide tension from respiratory depression have often led to suboptimal postoperative analgesic strategies in caring for neurosurgical patients. Neurosurgical patients may have difficulty or be incapable of communicating their need for analgesics due to neurologic deficits, which poses an additional challenge. Postoperative pain control should be a priority, because pain adversely affects recovery and patient outcomes. Inconsistent practices and the quality of current analgesic strategies for neurosurgical patients still leave room for improvement. Given the complexity of postoperative pain management for these patients, multimodal strategies are often required to optimize pain control and at the same time limit undesired side effects. PMID:26929661

  6. Simulation in neurosurgery: Past, present, and future.

    PubMed

    Suri, Ashish; Patra, Devi Prasad; Meena, Rajesh Kumar

    2016-01-01

    Neurosurgery is one of the most technically demanding medical professions that warrants a high level of expertise. In the present context of competitive medical practice, high societal expectations regarding quality of patient care and medicolegal and financial constraints, there are fewer opportunities for a trainee to achieve competency in standard neurosurgical, microsurgical, and operative techniques. Practice on simulation models like cadavers has been a trend since antiquity; however, recent development of newer models with their strategic modifications has given simulation education a new dimension. It has allowed trainees to acquire and improve surgical skills and knowledge in specifically fabricated and controlled settings with no risk to real patients. Simulation also offers the opportunity for deliberate practice and repetition unlimited number of times so that psychomotor skills can be automated. There is ever-growing evidence showing the positive impact of simulation on resident training in various areas of health care. Advances in computer technology and imaging, development of sophisticated virtual reality simulators with haptic feedback and the recent addition of three-dimensional printing technology, have opened a wide arena for the development of high-fidelity patient-specific models to complement current neurosurgical training. Simulation training in neurosurgery in India is still elementary since its inception at the All India Institute of Medical Sciences, New Delhi. A structured modular training program has been developed which is yet to be implemented at a multi-institutional level. Stringent efforts are needed to establish a uniform resident training curriculum where simulators can be used to complement current neurosurgical training. PMID:27147144

  7. The 2012 AANS Presidential Address. We are neurosurgery.

    PubMed

    McCormick, Paul C

    2012-12-01

    The theme of the 80th Annual Meeting of the American Association of Neurological Surgeons and the title of this presidential address, "We are neurosurgery," is a simple 3-word affirmation of who neurosurgeons are, what they have achieved, and how much there is yet to accomplish. Recent advances in neurobiology and the clinical neurosciences have brought an unprecedented understanding of the human nervous system in both health and disease. As a specialty, neurosurgery has translated knowledge, expanded techniques, and incorporated technology to exponentially expand the science and scope of neurosurgical practice. However, the rapidly advancing, divergently evolving growth of neurosurgery has had profound effects on all aspects of neurosurgery. In this address, the author examines the contemporary meaning of the annual meeting's theme as it relates to the science, practice, specialty, and profession of neurosurgery, as well as the neurosurgeon. In doing so, the author reveals his interpretation of "We are neurosurgery," which he hopes will have an effect on others. PMID:23198859

  8. The genesis of neurosurgery and the evolution of the neurosurgical operative environment: part I-prehistory to 2003.

    PubMed

    Liu, Charles Y; Apuzzo, Michael L J

    2003-01-01

    Despite its singular importance, little attention has been given to the neurosurgical operative environment in the scientific and medical literature. This article focuses attention on the development of neurosurgery and the parallel emergence of its operative setting. The operative environment has, to a large extent, defined the "state of the art and science" of neurosurgery, which is now undergoing rapid reinvention. During the course of its initial invention, major milestones in the development of neurosurgery have included the definition of anatomy, consolidation of a scientific basis, and incorporation of the practicalities of anesthesia and antisepsis and later operative technical adjuvants for further refinement of action and minimalism. The progress, previously long and laborious in emergence, is currently undergoing rapid evolution. Throughout its evolution, the discipline has assimilated the most effective tools of modernity into the operative environment, leading eventually to the entity known as the operating room. In the decades leading to the present, progressive minimalization of manipulation and the emergence of more refined operative definition with increasing precision are evident, with concurrent miniaturization of attendant computerized support systems, sensors, robotic interfaces, and imaging devices. These developments over time have led to the invention of neurosurgery and the establishment of the current state-of-the-art neurosurgical operating room as we understand it, and indeed, to a broader definition of the entity itself. To remain current, each neurosurgeon should periodically reconsider his or her personal operative environment and its functional design with reference to modernity of practice as currently defined. PMID:12493097

  9. Nonlinear optical imaging: toward chemical imaging during neurosurgery

    NASA Astrophysics Data System (ADS)

    Meyer, Tobias; Dietzek, Benjamin; Krafft, Christoph; Romeike, Bernd F. M.; Reichart, Rupert; Kalff, Rolf; Popp, Jürgen

    2011-03-01

    Tumor recognition and precise tumor margin detection presents a central challenge during neurosurgery. In this contribution we present our recent all-optical approach to tackle this problem. We introduce various nonlinear optical techniques, such as coherent anti-Stokes Raman scattering (CARS), second-harmonic generation (SHG) and two-photon fluorescence (TPEF), to study the morphology and chemical composition of (ex vivo) brain tissue. As the experimental techniques presented are contact-free all-optical techniques, which do not rely on the administration of external (fluorescence) labels, we anticipate that their implementation into surgical microscopes will provide significant advantages of intraoperative tumor diagnosis. In this contribution an introduction to the different optical spectroscopic methods will be presented and their implementation into a multimodal microscopic setup will be discussed. Furthermore, we will exemplify their application to brain tissue, i.e. both pig brain as a model for healthy brain tissue and human brain samples taken from surgical procedures. The data to be discussed show the capability of a joint CARS/SHG/TPEF multimodal imaging approach in highlighting various aspects of tissue morphochemistry. The consequences of this microspectroscopic potential, when combined with the existing technology of surgical microscopes, will be discussed.

  10. History of neurosurgery and neurosurgical applications in Turkey.

    PubMed

    Naderi, Sait; Erbengi, Aykut

    2005-01-01

    Although there is evidence of applications of cranial surgery in ancient times, it is commonly accepted that modern surgery started in the late 19th century. The advancements in anesthesiology and aseptic techniques were the main factors contributing to this process. Surgery of the nervous system, however, has a relatively shorter history than surgery of other systems. The process of surgical development in Turkey did not differ from most Western countries. Modern surgery started in 1890 in Turkey. In the beginning, neurosurgical applications were performed by general surgeons. Most of these applications included procedures for craniocerebral traumas and infections and procedures for pain relief. The first neurosurgeon, Dr. Tuner, started working in 1923, operating in some spinal cord and brain tumor and trigeminal neuralgia cases. Other neurosurgeons, Dr. Dilek, Dr. Baydur, and Dr. Kankat, were trained in France and started to work in the mid 1930s. The first neurosurgery department was established in Istanbul in 1923, and the first neurosurgery training program started in the late 1940s. Today, there are more than 50 neurosurgery training centers and more than 500 neurosurgeons in Turkey. There is an increasing number of publications by Turkish neurosurgeons, contributing to the total body of literature in neurosurgery. The current state of neurosurgery in Turkey is parallel to that of the advanced Western countries. PMID:16256833

  11. [Application of frameless neuronavigation in urgent neurosurgery].

    PubMed

    Krylov, V V; Burov, S A; Dash'ian, V G; Shaklunov, A A

    2008-01-01

    Application of a novel technique is analyzed. Frameless CT-based navigation was applied for planning of surgical approach in 92 patients aged 14 to 69 with acute intracranial hemorrhage of different etiology (43 cases of hypertensive hemorrhages, 10 cases of traumatic intracranial hematomas and 16 cases of secondary non-traumatic intracerebral hematomas). Comparative analysis of radioopaque markers and natural anatomical landmarks for registration of patients showed that anatomical landmarks are sufficient for surgical planning without significant distortion of approach trajectory (mean error was 2.2 +/- 1 mm) in supratentorial haemorrhage. This discovery simplified the application of neuronavigation in emergency cases. In posterior fossa hematomas additional radioopaque markers are essential due to absence of constant anatomical landmarks in occipital region. Applicatyion of frameless neuronavigation in surgical treatment of acute intracranial hemorrhages may diminish intraoperative damage to the brain tissue and decrease invasiveness of the operation because of high accuracy of planning of surgical approach. This technique has good perspectives in emergency neurosurgery. PMID:19062589

  12. Role of computer technology in neurosurgery.

    PubMed

    Abdelwahab, M G; Cavalcanti, D D; Preul, M C

    2010-08-01

    In the clinical office, during surgical planning, or in the operating room, neurosurgeons have been surrounded by the digital world either recreating old tools or introducing new ones. Technological refinements, chiefly based on the use of computer systems, have altered the modus operandi for neurosurgery. In the emergency room or in the office, patient data are entered, digitally dictated, or gathered from electronic medical records. Images from every modality can be examined on a Picture Archiving and Communication System (PACS) or can be seen remotely on cell phones. Surgical planning is based on high-resolution reconstructions, and microsurgical or radiosurgical approaches can be assessed precisely using stereotaxy. Tumor resection, abscess or hematoma evacuation, or the management of vascular lesions can be assisted intraoperatively by new imaging resources integrated into the surgical microscope. Mathematical models can dictate how a lesion may recur as well as how often a particular patient should be followed. Finally, virtual reality is being developed as a training tool for residents and surgeons by preoperatively simulating complex surgical scenarios. Altogether, computerization at each level of patient care has been affected by digital technology to help enhance the safety of procedures and thereby improve outcomes of patients undergoing neurosurgical procedures. PMID:20802430

  13. African neurosurgery, the 21st-century challenge.

    PubMed

    El-Fiki, Mohamed

    2010-04-01

    Two major challenges facing African neurosurgery include quality and quantity, in both recourses and personnel. Discrepancy is noted between the two poles, namely, the north and south of the continent and the sub-Saharan area. Although reasonably advanced in the north and south, neurosurgery remains poorly distributed and has multiple deficiencies. The sub-Saharan region, where the demand is high and services are scarce, suffers from a similar lack of both qualified personnel and well-equipped neurosurgical facilities. Insufficient state funding and research facilities aggravate the situation and discourage the few well-trained African neurosurgeons to practice in their homeland. For those who do return home, cultural, social, economical, and political issues hinder their performance and hence the quality of neurosurgery delivered in Africa. Strategies for rectification of these handicaps are presented, including the need for high-standard local training and support from international organizations. PMID:20849772

  14. Simulation in Neurosurgery-A Brief Review and Commentary.

    PubMed

    Cobb, Mary In-Ping Huang; Taekman, Jeffrey M; Zomorodi, Ali R; Gonzalez, L Fernando; Turner, Dennis A

    2016-05-01

    Neurosurgery is one of the most technically demanding and liable of all medical professionals. More than 75% of neurosurgical errors are deemed as preventable and technical in nature. Yet in a specialty that requires such high level of technical expertise, with large consequences for error, there are even fewer opportunities for residents in training to practice on the most complicated cases. Although there is no replacement for actual experiences in the operating room, interpersonal mentorship, coaching, and training, there is room to supplement residency education through simulation. Here we review the evidence to support surgical simulation, describe the strengths and weaknesses of existing technologies in direct neurosurgery specific and indirect simulation applications, and advocate for the development of more neurosurgery-specific applications using emerging kinetic technologies. PMID:26704209

  15. EXProt: a database for proteins with an experimentally verified function.

    PubMed

    Ursing, Björn M; van Enckevort, Frank H J; Leunissen, Jack A M; Siezen, Roland J

    2002-01-01

    EXProt is a non-redundant protein database containing a selection of entries from genome annotation projects and public databases, aimed at including only proteins with an experimentally verified function. In EXProt release 2.0 we have collected entries from the Pseudomonas aeruginosa community annotation project (PseudoCAP), the Escherichia coli genome and proteome database (GenProtEC) and the translated coding sequences from the Prokaryotes division of EMBL nucleotide sequence database, which are described as having an experimentally verified function. Each entry in EXProt has a unique ID number and contains information about the species, amino acid sequence, functional annotation and, in most cases, links to references in MEDLINE/PubMed and to the entry in the original database. EXProt is indexed in SRS at CMBI (http://www.cmbi.kun.nl/srs/) and can be searched with BLAST and FASTA through the EXProt web page (http://www.cmbi.kun.nl/EXProt/). PMID:11752251

  16. MINOP: development of a miniaturized endoscopic operation system for neurosurgery

    NASA Astrophysics Data System (ADS)

    Guber, Andreas E.; Wieneke, Paul

    1996-04-01

    Within the framework of R&D activities in the field of microsystems technology, the Institute for Microstructure Technology of Karlsruhe Research Center among others has started to improve the functionality of existing medicotechnical instruments by increased integration of microtechnical components. On the basis of microsystems fabrication techniques, completely novel medical endoscope systems have become feasible. In cooperation with clinical, technical and industrial partners, a novel endoscopic operation system based on microsystems technology is being developed by the Institute for Microstructure Technology and the Aesculap AG company, Tuttlingen within the framework of the MINOP joint project. This new system shall be applied above all in the field of neurosurgery. This newly conceived endosystem is characterized by a multitude of novelties. It can perform a number of both sensor and actor functions. Due to its extremely small outer diameter, it can be applied through minute openings. As a result of the integrated microfluidic control system, the flexible endoscope can be moved to the actual site of operation on a previously specified path. This will allow future bi- and triportal neuro-endoscopic interventions for critical operations in the brain area. The different lumina of the flexible endoscope fulfill various functions. Via the optical fibers, laser radiation may be led to the distal end of the endoscope. Using microtechnical fabrication methods, special plastic microlenses have been produced. The working channel can be applied for rinsing and removal. Furthermore, the cleaning of the optics or the taking of tissue samples are possible. If required, another laser fiber can be driven forward through the working channel for selective therapy. For the first time, high-performance microinstruments have been developed on the basis of novel materials. These instruments can be applied either through the working channel or through an additional trocar.

  17. [Clinical studies of cefoperazone in neurosurgery].

    PubMed

    Kitamura, K; Shimizu, T; Abe, H; Suzuki, J; Tanaka, R; Nagai, H; Yamamoto, S; Handa, H; Nishimoto, A; Matsuoka, K

    1986-01-01

    A multicenter trial consisting of 164 institutions through out Japan, has been conducted to study the transfer of cefoperazone (CPZ) into the cerebrospinal fluid (CSF), and the clinical effectiveness of CPZ as a therapeutic or prophylactic agent in neurosurgery. The levels of CPZ in serum and CSF were determined in 96 patients. After initial dose of 2 g CPZ (intravenous drip infusion for 30 minutes), the serum level of CPZ after 1 hour was 124.5 +/- 6.6 micrograms/ml (Mean +/- S.E.), and even after 6 hours, it maintained as high as 47.8 +/- 16.6 micrograms/ml. The peak CPZ levels in CSF in patients with normal or minimal impairment in blood-CSF-barrier (BCB) (group I) and in those of localized impairment in BCB (group II) were 1.0 +/- 0.5 micrograms/ml at 2 hours and 3.0 +/- 1.8 micrograms/ml at 3 hours, respectively. The highest CSF level was seen in patients with meningitis (group III) and showed 5.0 +/- 2.4 micrograms/ml at 6 hours. After multiple dose of 2 g CPZ (intravenous drip infusion for 30 minutes), the serum kinetics of CPZ were not significantly different from those obtained after initial dose. However, the CPZ levels in CSF were higher than those observed after initial dose in all 3 groups and were higher than MIC75 against relevant pathogens for meningitis such as Escherichia coli, Klebsiella pneumoniae and Staphylococcus aureus. Moreover, in group III peak level of CPZ in CSF exceeded the MIC75 against Pseudomonas aeruginosa which is also frequently isolated from patients with meningitis in neurosurgery. As a therapeutic agent CPZ administered as sole agent was effective in 42 out of 55 cases (76.4%) in meningitis, in 78 out of 116 cases (67.2%) in pneumonia and in 36 out of 47 cases (76.6%) in urinary tract infection (UTI). Its efficacy rate against all infections treated was 72.2% (184/255). Regarding CPZ's prophylactic use, 39 out of 514 cases (7.6%) were judged as having or possibly having infections as follows; meningitis (13/514, 2

  18. What can functional neuroimaging tell the experimental psychologist?

    PubMed

    Henson, Richard

    2005-02-01

    I argue here that functional neuroimaging data--which I restrict to the haemodynamic techniques of fMRI and PET--can inform psychological theorizing, provided one assumes a "systematic" function-structure mapping in the brain. In this case, imaging data simply comprise another dependent variable, along with behavioural data, that can be used to test competing theories. In particular, I distinguish two types of inference: function-to-structure deduction and structure-to-function induction. With the former inference, a qualitatively different pattern of activity over the brain under two experimental conditions implies at least one different function associated with changes in the independent variable. With the second type of inference, activity of the same brain region(s) under two conditions implies a common function, possibly not predicted a priori. I illustrate these inferences with imaging studies of recognition memory, short-term memory, and repetition priming. I then consider in greater detail what is meant by a "systematic" function-structure mapping and argue that, particularly for structure-to-function induction, this entails a one-to-one mapping between functional and structural units, although the structural unit may be a network of interacting regions and care must be taken over the appropriate level of functional/structural abstraction. Nonetheless, the assumption of a systematic function-structure mapping is a "working hypothesis" that, in common with other scientific fields, cannot be proved on independent grounds and is probably best evaluated by the success of the enterprise as a whole. I also consider statistical issues such as the definition of a qualitative difference and methodological issues such as the relationship between imaging and behavioural data. I finish by reviewing various objections to neuroimaging, including neophrenology, functionalism, and equipotentiality, and by observing some criticisms of current practice in the imaging

  19. Spinal neurosurgery with the head-mounted "Varioscope" microscope.

    PubMed

    Kuchta, J; Simons, P

    2009-05-01

    We present a preliminary report on the intra-operative use of a head-mounted microscope ("Varioscope" Leica HM500) in spinal neurosurgery. The Varioscope is a dynamic microscope mounted on a head-set. It weights 297 g and measures 73 x 120 x 63 mm (length x width x height). It offers an infinitely variable range of magnification from 3.6x to 7.2x. The working distance ranges from 300 to 600 mm. The field of view varies between 30-144 mm, depending on the selected enlargement factor and the working distance. In addition to the zoom function, the device offers a focus function (automatic or on demand). The optical elements for focus and zoom are located in two separate tubes which are mounted on a middle section containing the mechanical components as well as the receiver unit for the focussing elements. The lenses are adjusted by means of motor-driven push/pull cables. The autofocus works well in larger operative fields and a working distance between 30 and 60 cm. Nevertheless, when used in today's "keyhole" approaches, the autofocus is not helpful when operating in deep structures. Based on the satisfactory results achieved in our series, we can recommend the Varioscope, especially when no stationary microscope is available. The portable device can be packed in a suitcase and can travel with the consultant microsurgeon to different hospitals and distant units. The built-in video camera is ideal for patients, staff, assistant surgeons, and student education with real-time video monitoring of procedures from the microsurgeon's perspective. For daily microsurgery, we felt more comfortable with fixed, stationary operating microscopes. PMID:19711265

  20. Optimizing experimental design for comparing models of brain function.

    PubMed

    Daunizeau, Jean; Preuschoff, Kerstin; Friston, Karl; Stephan, Klaas

    2011-11-01

    This article presents the first attempt to formalize the optimization of experimental design with the aim of comparing models of brain function based on neuroimaging data. We demonstrate our approach in the context of Dynamic Causal Modelling (DCM), which relates experimental manipulations to observed network dynamics (via hidden neuronal states) and provides an inference framework for selecting among candidate models. Here, we show how to optimize the sensitivity of model selection by choosing among experimental designs according to their respective model selection accuracy. Using Bayesian decision theory, we (i) derive the Laplace-Chernoff risk for model selection, (ii) disclose its relationship with classical design optimality criteria and (iii) assess its sensitivity to basic modelling assumptions. We then evaluate the approach when identifying brain networks using DCM. Monte-Carlo simulations and empirical analyses of fMRI data from a simple bimanual motor task in humans serve to demonstrate the relationship between network identification and the optimal experimental design. For example, we show that deciding whether there is a feedback connection requires shorter epoch durations, relative to asking whether there is experimentally induced change in a connection that is known to be present. Finally, we discuss limitations and potential extensions of this work. PMID:22125485

  1. In touch with robotics: neurosurgery for the future.

    PubMed

    Nathoo, Narendra; Cavuşoğlu, M Cenk; Vogelbaum, Michael A; Barnett, Gene H

    2005-03-01

    The introduction of multiple front-end technologies during the past quarter century has generated an emerging futurism for the discipline of neurological surgery. Driven primarily by synergistic developments in science and engineering, neurosurgery has always managed to harness the potential of the latest technical developments. Robotics represents one such technology. Progress in development of this technology has resulted in new uses for robotic devices in our discipline, which are accompanied by new potential dangers and inherent risks. The recent surge in robot-assisted interventions in other disciplines suggests that this technology may be considered one of a spectrum of frontier technologies poised to fuel the development of neurosurgery and consolidate the era of minimalism. On a more practical level, if the introduction of robotics in neurosurgery proves beneficial, neurosurgeons will need to become facile with this technology and learn to harness its potential so that the best surgical results may be achieved in the least invasive manner. This article reviews the role of robotic technology in the context of neurosurgery. PMID:15730567

  2. Experimental assessment of presumed filtered density function models

    NASA Astrophysics Data System (ADS)

    Stetsyuk, V.; Soulopoulos, N.; Hardalupas, Y.; Taylor, A. M. K. P.

    2015-06-01

    Measured filtered density functions (FDFs) as well as assumed beta distribution model of mixture fraction and "subgrid" scale (SGS) scalar variance z '' 2 ¯ , used typically in large eddy simulations, were studied by analysing experimental data, obtained from two-dimensional planar, laser induced fluorescence measurements in isothermal swirling turbulent flows at a constant Reynolds number of 29 000 for different swirl numbers (0.3, 0.58, and 1.07). Two-dimensional spatial filtering, by using a box filter, was performed in order to obtain the filtered variables, namely, resolved mean and "subgrid" scale scalar variance. These were used as inputs for assumed beta distribution of mixture fraction and top-hat FDF shape estimates. The presumed beta distribution model, top-hat FDF, and the measured filtered density functions were used to integrate a laminar flamelet solution in order to calculate the corresponding resolved temperature. The experimentally measured FDFs varied with the flow swirl number and both axial and radial positions in the flow. The FDFs were unimodal at flow regions with low SGS scalar variance, z '' 2 ¯ < 0.01, and bimodal at regions with high SGS variance, z '' 2 ¯ > 0.02. Bimodal FDF could be observed for a filter size of approximately 1.5-2 times the Batchelor scale. Unimodal FDF could be observed for a filter size as large as four times the Batchelor scale under well-mixed conditions. In addition, two common computational models (a gradient assumption and a scale similarity model) for the SGS scalar variance were used with the aim to evaluate their validity through comparison with the experimental data. It was found that the gradient assumption model performed generally better than the scale similarity one.

  3. Inosine improves functional recovery after experimental traumatic brain injury.

    PubMed

    Dachir, Shlomit; Shabashov, Dalia; Trembovler, Victoria; Alexandrovich, Alexander G; Benowitz, Larry I; Shohami, Esther

    2014-03-25

    Despite years of research, no effective therapy is yet available for the treatment of traumatic brain injury (TBI). The most prevalent and debilitating features in survivors of TBI are cognitive deficits and motor dysfunction. A potential therapeutic method for improving the function of patients following TBI would be to restore, at least in part, plasticity to the CNS in a controlled way that would allow for the formation of compensatory circuits. Inosine, a naturally occurring purine nucleoside, has been shown to promote axon collateral growth in the corticospinal tract (CST) following stroke and focal TBI. In the present study, we investigated the effects of inosine on motor and cognitive deficits, CST sprouting, and expression of synaptic proteins in an experimental model of closed head injury (CHI). Treatment with inosine (100 mg/kg i.p. at 1, 24 and 48 h following CHI) improved outcome after TBI, significantly decreasing the neurological severity score (NSS, p<0.04 vs. saline), an aggregate measure of performance on several tasks. It improved non-spatial cognitive performance (object recognition, p<0.016 vs. saline) but had little effect on sensorimotor coordination (rotarod) and spatial cognitive functions (Y-maze). Inosine did not affect CST sprouting in the lumbar spinal cord but did restore levels of the growth-associated protein GAP-43 in the hippocampus, though not in the cerebral cortex. Our results suggest that inosine may improve functional outcome after TBI. PMID:24502983

  4. Mining experimental evidence of molecular function claims from the literature

    PubMed Central

    Crangle, Colleen E.; Cherry, J. Michael; Hong, Eurie L.; Zbyslaw, Alex; Wong, Limsoon

    2011-01-01

    Motivation The rate at which gene-related findings appear in the scientific literature makes it difficult if not impossible for biomedical scientists to keep fully informed and up to date. The importance of these findings argues for the development of automated methods that can find, extract and summarize this information. This article reports on methods for determining the molecular function claims that are being made in a scientific article, specifically those that are backed by experimental evidence. Results The most significant result is that for molecular function claims based on direct assays, our methods achieved recall of 70.7% and precision of 65.7%. Furthermore, our methods correctly identified in the text 44.6% of the specific molecular function claims backed up by direct assays, but with a precision of only 0.92%, a disappointing outcome that led to an examination of the different kinds of errors. These results were based on an analysis of 1823 articles from the literature of Saccharomyces cerevisiae (budding yeast). Availability The annotation files for S.cerevisiae are available from ftp://genome-ftp.stanford.edu/pub/yeast/data_download/literature_curation/gene_association.sgd.gz. The draft protocol vocabulary is available by request from the first author. Contact crangle@converspeech.com PMID:17942445

  5. Hugh Cairns and the origin of British neurosurgery.

    PubMed

    Tailor, J; Handa, A

    2007-04-01

    Sir Hugh Cairns, the first Nuffield Professor of Surgery in Oxford and consultant neurosurgeon to the Royal Army Medical Corps during World War II, was a leader in helping to establish neurosurgery as a speciality in Britain. After learning the craft from Dr Harvey Cushing in Boston, Cairns fought against the general surgical orthodoxy in London to establish the first specialised neurosurgical unit in a teaching hospital. We review his early life, training with Cushing, his inspiring character and administrative prowess which not only helped to win the battle for neurosurgery in London but also helped to establish the Oxford Clinical School and to save thousands of lives during the Second World War. PMID:17453787

  6. Cerenkov and radioluminescence imaging of brain tumor specimens during neurosurgery

    NASA Astrophysics Data System (ADS)

    Spinelli, Antonello Enrico; Schiariti, Marco P.; Grana, Chiara M.; Ferrari, Mahila; Cremonesi, Marta; Boschi, Federico

    2016-05-01

    We presented the first example of Cerenkov luminescence imaging (CLI) and radioluminescence imaging (RLI) of human tumor specimens. A patient with a brain meningioma localized in the left parietal region was injected with 166 MBq of Y90-DOTATOC the day before neurosurgery. The specimens of the tumor removed during surgery were imaged using both CLI and RLI using an optical imager prototype developed in our laboratory. The system is based on a cooled electron multiplied charge coupled device coupled with an f/0.95 17-mm C-mount lens. We showed for the first time the possibility of obtaining CLI and RLI images of fresh human brain tumor specimens removed during neurosurgery.

  7. Experimental moments of the nucleon structure function F2

    SciTech Connect

    Mikhail Osipenko; W. Melnitchouk; Silvano Simula; Sergey Kulagin; Giovanni Ricco

    2007-12-01

    Experimental data on the F2 structure functions of the proton and deuteron, including recent results from CLAS at Jefferson Lab, have been used to construct their n<=12 moments. A comprehensive analysis of the moments in terms of the operator product expansion has been performed to separate the moments into leading and higher twist contributions. Particular attention was paid to the issue of nuclear corrections in the deuteron, when extracting the neutron moments from data. The difference between the proton and neutron moments was compared directly with lattice QCD simulations. Combining leading twist moments of the neutron and proton we found the d/u ratio at x->1 approaching 0, although the precision of the data did not allow to exclude the 1/5 value. The higher twist components of the proton and neutron moments suggest that multi-parton correlations are isospin independent.

  8. Experimental investigations of the functional morphology of dragonfly wings

    NASA Astrophysics Data System (ADS)

    Rajabi, H.; Darvizeh, A.

    2013-08-01

    Nowadays, the importance of identifying the flight mechanisms of the dragonfly, as an inspiration for designing flapping wing vehicles, is well known. An experimental approach to understanding the complexities of insect wings as organs of flight could provide significant outcomes for design purposes. In this paper, a comprehensive investigation is carried out on the morphological and microstructural features of dragonfly wings. Scanning electron microscopy (SEM) and tensile testing are used to experimentally verify the functional roles of different parts of the wings. A number of SEM images of the elements of the wings, such as the nodus, leading edge, trailing edge, and vein sections, which play dominant roles in strengthening the whole structure, are presented. The results from the tensile tests indicate that the nodus might be the critical region of the wing that is subjected to high tensile stresses. Considering the patterns of the longitudinal corrugations of the wings obtained in this paper, it can be supposed that they increase the load-bearing capacity, giving the wings an ability to tolerate dynamic loading conditions. In addition, it is suggested that the longitudinal veins, along with the leading and trailing edges, are structural mechanisms that further improve fatigue resistance by providing higher fracture toughness, preventing crack propagation, and allowing the wings to sustain a significant amount of damage without loss of strength.

  9. Application of the Chick Embryo Chorioallantoic Membrane in Neurosurgery Disease

    PubMed Central

    Yuan, Yong-Jie; Xu, Kan; Wu, Wei; Luo, Qi; Yu, Jin-Lu

    2014-01-01

    The chick embryo chorioallantoic membrane (CAM) is a highly vascularized extraembryonic membrane. Because of its ease of accessibility, extensive vascularization and immunodeficient environment, the CAM has been broadly used in the oncology, biology, pharmacy, and tissue regeneration research. The present review summarizes the application of the CAM in neurosurgery disease research. We focused on the use of the CAM as an assay for the research of glioma, vascular anomalies, Moyamoya Disease, and the blood-brain barrier. PMID:25419173

  10. Multitrophic functional diversity predicts ecosystem functioning in experimental assemblages of estuarine consumers.

    PubMed

    Lefcheck, Jonathan S; Duffy, J Emmett

    2015-11-01

    The use of functional traits to explain how biodiversity affects ecosystem functioning has attracted intense interest, yet few studies have a priori altered functional diversity, especially in multitrophic communities. Here, we manipulated multivariate functional diversity of estuarine grazers and predators within multiple levels of species richness to test how species richness and functional diversity predicted ecosystem functioning in a multitrophic food web. Community functional diversity was a better predictor than species richness for the majority of ecosystem properties, based on generalized linear mixed-effects models. Combining inferences from eight traits into a single multivariate index increased prediction accuracy of these models relative to any individual trait. Structural equation modeling revealed that functional diversity of both grazers and predators was important in driving final biomass within trophic levels, with stronger effects observed for predators. We also show that different species drove different ecosystem responses, with evidence for both sampling effects and complementarity. Our study extends experimental investigations of functional trait diversity to a multilevel food web, and demonstrates that functional diversity can be more accurate and effective than species richness in predicting community biomass in a food web context. PMID:27070016

  11. Improving on-time start for iMRI neurosurgeries

    PubMed Central

    Ghadiali, Natascha Fherzinah Rustom; Koh, Darren; Chia, Kuok Wei; Quek, Shin Yi

    2013-01-01

    Background: In the Singapore General Hospital, intraoperative MRI (iMRI) neurosurgery is a multi-disciplinary process that involves staff from multiple departments. However, a baseline analysis showed that only 10.5% of iMRI neurosurgeries start on time, resulting in unnecessary waste of resources. The project aimed to improve the percentage of on-time start iMRI neurosurgeries to 100% within nine months. Materials and Methods: Clinical Practice Improvement methodology was used. The project involves four phases: Diagnostic, in which a baseline analysis is conducted; Intervention, in which problem areas are identified; Implementation, in which potential solutions are implemented; and sustaining, in which strategies to sustain gains are discussed. Results: The percentage of on-time start cases gradually increased to 100% in eight months, and was sustained above 85% in the following five months. Conclusion: This project serves as a successful demonstration of how quality improvement can be effected in a complex, multidisciplinary workflow, which is the norm for many hospital procedures. PMID:23741256

  12. Experimental nonalcoholic steatohepatitis compromises ureagenesis, an essential hepatic metabolic function.

    PubMed

    Thomsen, Karen Louise; Grønbæk, Henning; Glavind, Emilie; Hebbard, Lionel; Jessen, Niels; Clouston, Andrew; George, Jacob; Vilstrup, Hendrik

    2014-08-01

    Nonalcoholic steatohepatitis (NASH) is increasing in prevalence, yet its consequences for liver function are unknown. We studied ureagenesis, an essential metabolic liver function of importance for whole body nitrogen homeostasis, in a rodent model of diet-induced NASH. Rats were fed a high-fat, high-cholesterol diet for 4 and 16 wk, resulting in early and advanced experimental NASH, respectively. We examined the urea cycle enzyme mRNAs in liver tissue, the hepatocyte urea cycle enzyme proteins, and the in vivo capacity of urea-nitrogen synthesis (CUNS). Early NASH decreased all of the urea cycle mRNAs to an average of 60% and the ornithine transcarbamylase protein to 10%, whereas the CUNS remained unchanged. Advanced NASH further decreased the carbamoyl phosphate synthetase protein to 63% and, in addition, decreased the CUNS by 20% [from 5.65 ± 0.23 to 4.58 ± 0.30 μmol × (min × 100 g)(-1); P = 0.01]. Early NASH compromised the genes and enzyme proteins involved in ureagenesis, whereas advanced NASH resulted in a functional reduction in the capacity for ureagenesis. The pattern of urea cycle perturbations suggests a prevailing mitochondrial impairment by NASH. The decrease in CUNS has consequences for the ability of the body to adjust to changes in the requirements for nitrogen homeostasis e.g., at stressful events. NASH, thus, in terms of metabolic consequences, is not an innocuous lesion, and the manifestations of the damage seem to be a continuum with increasing disease severity. PMID:24924745

  13. Network inference from functional experimental data (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Desrosiers, Patrick; Labrecque, Simon; Tremblay, Maxime; Bélanger, Mathieu; De Dorlodot, Bertrand; Côté, Daniel C.

    2016-03-01

    Functional connectivity maps of neuronal networks are critical tools to understand how neurons form circuits, how information is encoded and processed by neurons, how memory is shaped, and how these basic processes are altered under pathological conditions. Current light microscopy allows to observe calcium or electrical activity of thousands of neurons simultaneously, yet assessing comprehensive connectivity maps directly from such data remains a non-trivial analytical task. There exist simple statistical methods, such as cross-correlation and Granger causality, but they only detect linear interactions between neurons. Other more involved inference methods inspired by information theory, such as mutual information and transfer entropy, identify more accurately connections between neurons but also require more computational resources. We carried out a comparative study of common connectivity inference methods. The relative accuracy and computational cost of each method was determined via simulated fluorescence traces generated with realistic computational models of interacting neurons in networks of different topologies (clustered or non-clustered) and sizes (10-1000 neurons). To bridge the computational and experimental works, we observed the intracellular calcium activity of live hippocampal neuronal cultures infected with the fluorescent calcium marker GCaMP6f. The spontaneous activity of the networks, consisting of 50-100 neurons per field of view, was recorded from 20 to 50 Hz on a microscope controlled by a homemade software. We implemented all connectivity inference methods in the software, which rapidly loads calcium fluorescence movies, segments the images, extracts the fluorescence traces, and assesses the functional connections (with strengths and directions) between each pair of neurons. We used this software to assess, in real time, the functional connectivity from real calcium imaging data in basal conditions, under plasticity protocols, and epileptic

  14. Platelet Function During Hypothermia in Experimental Mock Circulation.

    PubMed

    Van Poucke, Sven; Stevens, Kris; Kicken, Cécile; Simons, Antoine; Marcus, Abraham; Lancé, Marcus

    2016-03-01

    for platelet stimulation using COL, this trend continues during temperature drop from 37°C to 32°C. LTA values using AA and TRAP demonstrate a considerable decline in platelet function throughout the experiment that was most pronounced after 24 h of circulation at 32°C. LTA values using ADP and COL further decline after rewarming. MEA ADP, ASPI, and COL identify platelet dysfunction patterns analogous with LTA, between the start of the mock circulation and the start of cooling. Except for MEA TRAP, this trend continues during temperature drop from 37°C to 32°C. MEA ASPI and ADP demonstrate a considerable decline in platelet function throughout the experiment, which was most pronounced after 24 h of circulation at 32°C. For MEA COL and TRAP, further decline in platelet function is observed after rewarming. This study quantitatively assessed the effect of temperature changes on platelet function during experimental mock circulation demonstrating a considerable decline in platelet function during hypothermia without uniform recovery of platelet function observed after rewarming. PMID:26411987

  15. Critical Zone Experimental Design to Assess Soil Processes and Function

    NASA Astrophysics Data System (ADS)

    Banwart, Steve

    2010-05-01

    experimental design studies soil processes across the temporal evolution of the soil profile, from its formation on bare bedrock, through managed use as productive land to its degradation under longstanding pressures from intensive land use. To understand this conceptual life cycle of soil, we have selected 4 European field sites as Critical Zone Observatories. These are to provide data sets of soil parameters, processes and functions which will be incorporated into the mathematical models. The field sites are 1) the BigLink field station which is located in the chronosequence of the Damma Glacier forefield in alpine Switzerland and is established to study the initial stages of soil development on bedrock; 2) the Lysina Catchment in the Czech Republic which is representative of productive soils managed for intensive forestry, 3) the Fuchsenbigl Field Station in Austria which is an agricultural research site that is representative of productive soils managed as arable land and 4) the Koiliaris Catchment in Crete, Greece which represents degraded Mediterranean region soils, heavily impacted by centuries of intensive grazing and farming, under severe risk of desertification.

  16. Functional genomic hypothesis generation and experimentation by a robot scientist.

    PubMed

    King, Ross D; Whelan, Kenneth E; Jones, Ffion M; Reiser, Philip G K; Bryant, Christopher H; Muggleton, Stephen H; Kell, Douglas B; Oliver, Stephen G

    2004-01-15

    The question of whether it is possible to automate the scientific process is of both great theoretical interest and increasing practical importance because, in many scientific areas, data are being generated much faster than they can be effectively analysed. We describe a physically implemented robotic system that applies techniques from artificial intelligence to carry out cycles of scientific experimentation. The system automatically originates hypotheses to explain observations, devises experiments to test these hypotheses, physically runs the experiments using a laboratory robot, interprets the results to falsify hypotheses inconsistent with the data, and then repeats the cycle. Here we apply the system to the determination of gene function using deletion mutants of yeast (Saccharomyces cerevisiae) and auxotrophic growth experiments. We built and tested a detailed logical model (involving genes, proteins and metabolites) of the aromatic amino acid synthesis pathway. In biological experiments that automatically reconstruct parts of this model, we show that an intelligent experiment selection strategy is competitive with human performance and significantly outperforms, with a cost decrease of 3-fold and 100-fold (respectively), both cheapest and random-experiment selection. PMID:14724639

  17. Experimental Study of Functionally Graded Beam with Fly Ash

    NASA Astrophysics Data System (ADS)

    Bajaj, K.; Shrivastava, Y.; Dhoke, P.

    2013-11-01

    Generally, concrete used in the field suffers from lack of durability and homogeneity. As cement is the only binding material in concrete and due to hike in its price, researchers have been looking for apt substitutes. For the sake of economy, strength and anti-corrosion functionally graded beam (FGB) has developed having one layer of normal concrete and another of high volume fly-ash concrete (HVFAC). The flexural behavior FGB has analyzed experimentally in this work with variation in interface as 0, 25, 50, 75 and 100 from bottom. In this study, HVFAC has prepared with replacement of cement by 20, 35 and 55 % with fly ash for M20 and M30 grade of concrete. It has seemed that there is 12.86 and 3.56 % increase in compressive and flexural strength of FGB. The bond strength FGM cube is optimum at 50 mm depth. As FGM is economical, having more durability and strength, so its adoption enables more sustainability in concrete industry.

  18. Naval aviation and neurosurgery: traditions, commonalities, and lessons learned. The 2007 presidential address.

    PubMed

    Quest, Donald O

    2007-12-01

    In his presidential address to the American Association of Neurological Surgeons, the author recounts lessons he learned while training to be a Naval Aviator and later a neurosurgeon. He describes his life as an aviator and neurosurgeon, compares naval aviation and neurosurgery, and points out lessons that neurosurgery can learn from naval aviation. PMID:18077941

  19. Dr. Lenke Horvath (1917-1991): Creator of Pediatric Neurosurgery in Romania.

    PubMed

    Mohan, Dumitru; Moisa, Horatiu Alexandru; Nica, Dan Aurel; Ciurea, Alexandru Vlad

    2016-04-01

    The development of neurosurgery as an independent specialty took place with great difficulty in Romania. In this respect, the most revered personalities are those of Professor Alexandru Moruzzi (1900-1957) (in Iasi) and Professor Dimitrie Bagdasar (1893-1946) (in Bucharest), who are the fathers of modern neurosurgery in Romania. Professor Bagdasar was schooled in Professor Harvey Cushing's clinic in Boston and is credited with creating the first completely independent neurosurgical unit in Romania. His legacy was carried on with honor by Professor Constantin Arseni (1912-1994), who, in 1975, tasked Dr. Lenke Horvath (1917-1991) with creating the first autonomous pediatric neurosurgery unit in Bucharest. This article is a small tribute to the founder of pediatric neurosurgery in Romania and one of the female pioneer neurosurgeons, who, by personal example of dedication and hard work, radically changed medical thinking and neurosurgery in Romania. PMID:26211853

  20. Robot-assisted microscope for neurosurgery.

    PubMed

    Giorgi, C; Eisenberg, H; Costi, G; Gallo, E; Garibotto, G; Casolino, D S

    1995-01-01

    We describe the implementation of a robotic arm connected to a neurosurgical operative microscope. A force feedback sensor drives the motors of the arm in response to the positioning of the microscope by the surgeon. Computer graphic techniques allow tracking of the current position of the microscope within the volumetric reconstruction of the brain. The integration of the prototype into the neurosurgical operating room is currently being evaluated. Preliminary comments on this experimental phase are offered. PMID:9079441

  1. Checklists in Neurosurgery to Decrease Preventable Medical Errors: A Review.

    PubMed

    Enchev, Yavor

    2015-10-01

    Neurosurgery represents a zero tolerance environment for medical errors, especially preventable ones like all types of wrong site surgery, complications due to the incorrect positioning of patients for neurosurgical interventions and complications due to failure of the devices required for the specific procedure. Following the excellent and encouraging results of the safety checklists in intensive care medicine and in other surgical areas, the checklist was naturally introduced in neurosurgery. To date, the reported world experience with neurosurgical checklists is limited to 15 series with fewer than 20,000 cases in various neurosurgical areas. The purpose of this review was to study the reported neurosurgical checklists according to the following parameters: year of publication; country of origin; area of neurosurgery; type of neurosurgical procedure-elective or emergency; person in charge of the checklist completion; participants involved in completion; whether they prevented incorrect site surgery; whether they prevented complications due to incorrect positioning of the patients for neurosurgical interventions; whether they prevented complications due to failure of the devices required for the specific procedure; their specific aims; educational preparation and training; the time needed for checklist completion; study duration and phases; number of cases included; barriers to implementation; efforts to implementation; team appreciation; and safety outcomes. Based on this analysis, it could be concluded that neurosurgical checklists represent an efficient, reliable, cost-effective and time-saving tool for increasing patient safety and elevating the neurosurgeons' self-confidence. Every neurosurgical department must develop its own neurosurgical checklist or adopt and modify an existing one according to its specific features and needs in an attempt to establish or develop its safety culture. The world, continental, regional and national neurosurgical societies

  2. Checklists in Neurosurgery to Decrease Preventable Medical Errors: A Review

    PubMed Central

    Enchev, Yavor

    2015-01-01

    Neurosurgery represents a zero tolerance environment for medical errors, especially preventable ones like all types of wrong site surgery, complications due to the incorrect positioning of patients for neurosurgical interventions and complications due to failure of the devices required for the specific procedure. Following the excellent and encouraging results of the safety checklists in intensive care medicine and in other surgical areas, the checklist was naturally introduced in neurosurgery. To date, the reported world experience with neurosurgical checklists is limited to 15 series with fewer than 20,000 cases in various neurosurgical areas. The purpose of this review was to study the reported neurosurgical checklists according to the following parameters: year of publication; country of origin; area of neurosurgery; type of neurosurgical procedure-elective or emergency; person in charge of the checklist completion; participants involved in completion; whether they prevented incorrect site surgery; whether they prevented complications due to incorrect positioning of the patients for neurosurgical interventions; whether they prevented complications due to failure of the devices required for the specific procedure; their specific aims; educational preparation and training; the time needed for checklist completion; study duration and phases; number of cases included; barriers to implementation; efforts to implementation; team appreciation; and safety outcomes. Based on this analysis, it could be concluded that neurosurgical checklists represent an efficient, reliable, cost-effective and time-saving tool for increasing patient safety and elevating the neurosurgeons’ self-confidence. Every neurosurgical department must develop its own neurosurgical checklist or adopt and modify an existing one according to its specific features and needs in an attempt to establish or develop its safety culture. The world, continental, regional and national neurosurgical societies

  3. Highly cited publications in pediatric neurosurgery: part 2

    PubMed Central

    Khan, Nickalus R.; Auschwitz, Tyler; McAbee, Joseph H.; Boop, Frederick A.; Klimo, Paul

    2015-01-01

    Purpose Citation counting can be used to evaluate the impact an article has made on its discipline. This study characterizes the most cited articles related to clinical pediatric neurosurgery as of July 2013. Methods A list of search terms was computed using Thomson Reuters Web of Science® (WOS) to capture the 100 most cited articles in the overall literature and the top 50 articles from 2002 to 2012 related to clinical pediatric neurosurgery from non-dedicated pediatric neurosurgical journals. The following information was recorded for each article: number of authors, country of origin, citation count adjusted for number of years in print, topic, and level of evidence. Results The 100 most cited articles appeared in 44 journals. Publication dates ranged from 1986 to 2008; two were class 1 evidence, nine class 2, 26 class 3, and 52 class 4. Citations ranged from 90 to 321 (mean=131); average time-adjusted citation count was 10. The 50 most cited articles from 2002 to 2012 appeared in 31 journals; four were class 2 evidence, 15 class 3, and 21 class 4. Citations ranged from 68 to 245 (mean=103); average time-adjusted citation count was 13. Conclusion Overall, papers from non-pediatric neurosurgical journals had higher citation counts and improved level of evidence grades compared to articles from pediatric neurosurgical periodicals. An original paper related to clinical pediatric neurosurgery in a non-pediatric neurosurgical journal having a total citation count of 100–150 or more and an average citation count of 10–15 per year or more can be considered a high-impact publication. PMID:24113776

  4. Intraoperative neurosonography revisited: effective neuronavigation in pediatric neurosurgery

    PubMed Central

    2015-01-01

    Intraoperative ultrasonography (IOUS) is a widely used noninvasive method to evaluate the morphology, vasculature, and pathologies of the brain. The advantages of IOUS include realtime depiction of neuroanatomy, accurate localization and characterization of a lesion, reduced surgical exploration and surgical time, and presumably decreased patient morbidity. IOUS is useful in the intraoperative monitoring of lesion resection as well as intraoperative localization and characterization of focal parenchymal lesions. This review aims to provide an overview of the clinical application of IOUS in pediatric intracranial neurosurgery. PMID:25672771

  5. Publication misrepresentation among neurosurgery residency applicants: an increasing problem.

    PubMed

    Kistka, Heather M; Nayeri, Arash; Wang, Li; Dow, Jamie; Chandrasekhar, Rameela; Chambless, Lola B

    2016-01-01

    OBJECT Misrepresentation of scholarly achievements is a recognized phenomenon, well documented in numerous fields, yet the accuracy of reporting remains dependent on the honor principle. Therefore, honest self-reporting is of paramount importance to maintain scientific integrity in neurosurgery. The authors had observed a trend toward increasing numbers of publications among applicants for neurosurgery residency at Vanderbilt University and undertook this study to determine whether this change was a result of increased academic productivity, inflated reporting, or both. They also aimed to identify application variables associated with inaccurate citations. METHODS The authors retrospectively reviewed the residency applications submitted to their neurosurgery department in 2006 (n = 148) and 2012 (n = 194). The applications from 2006 were made via SF Match and those from 2012 were made using the Electronic Residency Application Service. Publications reported as "accepted" or "in press" were verified via online search of Google Scholar, PubMed, journal websites, and direct journal contact. Works were considered misrepresented if they did not exist, incorrectly listed the applicant as first author, or were incorrectly listed as peer reviewed or published in a printed journal rather than an online only or non-peer-reviewed publication. Demographic data were collected, including applicant sex, medical school ranking and country, advanced degrees, Alpha Omega Alpha membership, and USMLE Step 1 score. Zero-inflated negative binomial regression was used to identify predictors of misrepresentation. RESULTS Using univariate analysis, between 2006 and 2012 the percentage of applicants reporting published works increased significantly (47% vs 97%, p < 0.001). However, the percentage of applicants with misrepresentations (33% vs 45%) also increased. In 2012, applicants with a greater total of reported works (p < 0.001) and applicants from unranked US medical schools (those not

  6. Neurosurgery Education and Development program to treat hydrocephalus and to develop neurosurgery in Africa using mobile neuroendoscopic training.

    PubMed

    Piquer, José; Qureshi, Mubashir Mahmood; Young, Paul H; Dempsey, Robert J

    2015-06-01

    OBJECT A shortage of neurosurgeons and a lack of knowledge of neuroendoscopic management of hydrocephalus limits modern care in sub-Saharan Africa. Hence, a mobile teaching project for endoscopic third ventriculostomy (ETV) procedures and a subsequent program to develop neurosurgery as a permanent specialty in Kenya and Zanzibar were created and sponsored by the Neurosurgery Education and Development (NED) Foundation and the Foundation for International Education in Neurological Surgery. The objective of this work was to evaluate the results of surgical training and medical care in both projects from 2006 to 2013. METHODS Two portable neuroendoscopy systems were purchased and a total of 38 ETV workshops were organized in 21 hospitals in 7 different countries. Additionally, 49 medical expeditions were dispatched to the Coast General Hospital in Mombasa, Kenya, and to the Mnazi Moja Hospital in Zanzibar. RESULTS From the first project, a total of 376 infants with hydrocephalus received surgery. Six-month follow-up was achieved in 22%. In those who received follow-up, ETV efficacy was 51%. The best success rates were achieved with patients 1 year of age or older with aqueductal stenosis (73%). The main causes of hydrocephalus were infection (56%) and spina bifida (23%). The mobile education program interacted with 72 local surgeons and 122 nurses who were trained in ETV procedures. The second project involved 49 volunteer neurosurgeons who performed a total of 360 nonhydrocephalus neurosurgical operations since 2009. Furthermore, an agreement with the local government was signed to create the Mnazi Mmoja NED Institute in Zanzibar. CONCLUSIONS Mobile endoscopic treatment of hydrocephalus in East Africa results in reasonable success rates and has also led to major developments in medicine, particularly in the development of neurosurgery specialty care sites. PMID:25745948

  7. Construction of spline functions in spreadsheets to smooth experimental data

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A previous manuscript detailed how spreadsheet software can be programmed to smooth experimental data via cubic splines. This addendum corrects a few errors in the previous manuscript and provides additional necessary programming steps. ...

  8. A critical analysis of the current state of neurosurgery training in Pakistan

    PubMed Central

    Shamim, M. Shahzad; Tahir, M. Zubair; Godil, Saniya Siraj; Kumar, Rajesh; Siddiqui, Arshad Ali

    2011-01-01

    Objective: To observe interdepartmental variation in the availability of resources and academic activities within the various neurosurgery programs of Pakistan. Methods: This was a proforma-based survey of neurosurgery trainees and young neurosurgeons of Pakistan, looking at the academic infrastructure and output of their programs. The proforma was filled by 36 respondents from 11 neurosurgery centers of the country. All these centers were accredited for neurosurgery training in Pakistan. Results: Out of the 36 respondents, 30 were completing a Fellowship training (FCPS) and six were enrolled for a Master in Surgery (MS) program. About 80% of the participants used the Youman's Textbook of Neurosurgery as a reference book. Only 40% of the candidates had access to more than one indexed neurosurgery journal. Structured academic sessions (e.g., journal clubs and neuropathology meetings) were lacking in a majority of the training institutes, 95% of the trainees had no microsurgical laboratory experience, and modern neurosurgical tools (frameless neuronavigation system, neuroendoscopy) were in use at a few centers only. Conclusion: Neurosurgery training in Pakistan is not uniform and wide variations exist between the programs at the centers evaluated. We recommend exchange programs between centers at national and international levels, to allow trainees to gain first-hand exposure to training components not available in their own center. PMID:22276237

  9. Virtual reality simulation in neurosurgery: technologies and evolution.

    PubMed

    Chan, Sonny; Conti, François; Salisbury, Kenneth; Blevins, Nikolas H

    2013-01-01

    Neurosurgeons are faced with the challenge of learning, planning, and performing increasingly complex surgical procedures in which there is little room for error. With improvements in computational power and advances in visual and haptic display technologies, virtual surgical environments can now offer potential benefits for surgical training, planning, and rehearsal in a safe, simulated setting. This article introduces the various classes of surgical simulators and their respective purposes through a brief survey of representative simulation systems in the context of neurosurgery. Many technical challenges currently limit the application of virtual surgical environments. Although we cannot yet expect a digital patient to be indistinguishable from reality, new developments in computational methods and related technology bring us closer every day. We recognize that the design and implementation of an immersive virtual reality surgical simulator require expert knowledge from many disciplines. This article highlights a selection of recent developments in research areas related to virtual reality simulation, including anatomic modeling, computer graphics and visualization, haptics, and physics simulation, and discusses their implication for the simulation of neurosurgery. PMID:23254804

  10. Bradford's law: identification of the core journals for neurosurgery and its subspecialties.

    PubMed

    Venable, Garrett T; Shepherd, Brandon A; Loftis, Christopher M; McClatchy, S Gray; Roberts, Mallory L; Fillinger, Meghan E; Tansey, James B; Klimo, Paul

    2016-02-01

    OBJECT Bradford's law describes the scatter of citations for a given subject or field. It can be used to identify the most highly cited journals for a field or subject. The objective of this study was to use currently accepted formulations of Bradford's law to identify core journals of neurosurgery and neurosurgical subspecialties. METHODS All original research publications from 2009 to 2013 were analyzed for the top 25 North American academic neurosurgeons from each subspecialty. The top 25 were chosen from a ranked career h-index list identified from previous studies. Egghe's formulation and the verbal formulation of Bradford's law were applied to create specific citation density zones and identify the core journals for each subspecialty. The databases were then combined to identify the core journals for all of academic neurosurgery. RESULTS Using Bradford's verbal law with 4 zone models, the authors were able to identify the core journals of neurosurgery and its subspecialties. The journals found in the most highly cited first zone are presented here as the core journals. For neurosurgery as a whole, the core included the following journals: Journal of Neurosurgery, Neurosurgery, Spine, Stroke, Neurology, American Journal of Neuroradiology, International Journal of Radiation Oncology Biology Physics, and New England Journal of Medicine. The core journals for each subspecialty are presented in the manuscript. CONCLUSIONS Bradford's law can be used to identify the core journals of neurosurgery and its subspecialties. The core journals vary for each neurosurgical subspecialty, but Journal of Neurosurgery and Neurosurgery are among the core journals for each neurosurgical subspecialty. PMID:26339849

  11. Alzheimer's disease: The role for neurosurgery

    PubMed Central

    Pereira, Julio Leonardo Barbosa; Downes, Angela; Gorgulho, Alessandra; Patel, Vishal; Malkasian, Dennis; De Salles, Antonio

    2014-01-01

    Dementia, most commonly caused by Alzheimer's disease (AD), affects approximately 35 million people worldwide, with the incidence expected to increase as the population ages. After decades of investigation, AD is now understood to be a complex disease that affects behavior and cognition through several mechanisms: Disrupted neuronal communication, abnormal regional tissue metabolism, and impaired cellular repair. Existing therapies have demonstrated limited efficacy, which has spurred the search for specific disease markers and predictors as well as innovative therapeutic options. Deep brain stimulation (DBS) of the memory circuits is one such option, with early studies suggesting that modulation of neural activity in these networks may improve cognitive function. Encapsulated cell biodelivery (ECB) is a device that delivers nerve growth factor to the cholinergic basal forebrain to potentially improve cognitive decline in AD patients. This review discusses the pathogenesis of AD, novel neuroimaging and biochemical markers, and the emerging role for neurosurgical applications such as DBS and ECB. PMID:25289167

  12. The development of neurosurgery at the University of Utah, 1955-2009.

    PubMed

    House, Paul A; Heilbrun, M Peter; Apfelbaum, Ronald I; Kraus, Kristin L; Couldwell, William T

    2010-09-01

    Located in the geographic Intermountain West, the Department of Neurosurgery at the University of Utah has undergone remarkable growth and transformation since the appointment of the first full-time clinical faculty member in 1955. The Department has provided broad neurosurgical services to an expanding community while fulfilling its academic mission of pushing the frontiers within neurosurgical subspecialties. The history of neurosurgery in the Salt Lake Valley and the achievements of the Department of Neurosurgery, including the seminal development of early cranial stereotactic devices, are reviewed in this article. PMID:20651622

  13. Animal Structures and Functions, Science (Experimental): 5314.13.

    ERIC Educational Resources Information Center

    Silver, Barbara A.

    This unit of instruction was designed to introduce the student to the relationship between structure and function in the animal kingdom, with emphasis given to: (1) the evolution of physiological systems in the major animal phyla, (2) the complementarity of structure and function, and (3) the concept of homeostasis. The booklet lists the relevant…

  14. The Motivational Function of Private Speech: An Experimental Approach.

    ERIC Educational Resources Information Center

    de Dios, M. J.; Montero, I.

    Recently, some works have been published exploring the role of private speech as a tool for motivation, reaching beyond the classical research on its regulatory function for cognitive processes such as attention or executive function. In fact, the authors' own previous research has shown that a moderate account of spontaneous private speech of…

  15. Experimental Economics for Teaching the Functioning of Electricity Markets

    ERIC Educational Resources Information Center

    Guevara-Cedeno, J. Y.; Palma-Behnke, R.; Uribe, R.

    2012-01-01

    In the field of electricity markets, the development of training tools for engineers has been extremely useful. A novel experimental economics approach based on a computational Web platform of an electricity market is proposed here for the practical teaching of electrical engineering students. The approach is designed to diminish the gap that…

  16. The g2 Structure Function: An Experimental Overview

    SciTech Connect

    Slifer, Karl

    2009-08-01

    We will discuss recent results for the spin structure functions, with an emphasis on g2 . High precision g2 data allows for tests of the Burkhardt-Cottingham sum rule, and is needed to consistently evaluate higher twist effects.

  17. Influence of experimental hypokinesia on gastric secretory function

    NASA Technical Reports Server (NTRS)

    Markova, O. O.; Vavryshchuk, V. I.; Rozvodovskyy, V. I.; Proshcheruk, V. A.

    1980-01-01

    The gastric secretory function of rats was studied in 4, 8, 16 and 30 day hypokinesia. Inhibition of both the gastric juice secretory and acid producing functions was found. The greatest inhibition was observed on day 8 of limited mobility. By days 16 and 30 of the experiment, a tendency of the gastric secretory activity to return to normal was observed, although it remained reduced.

  18. Threats to academic neurosurgery in the United Kingdom: a personal view.

    PubMed Central

    Pickard, J D

    1993-01-01

    Money, or lack of it, is but one, albeit very important, threat to academic neurosurgery. This review has rambled over some of the other minefields and self-inflicted hurdles. The path of academic progress is long and tortuous. Time has to be found in neurosurgery to examine critically the opportunities and threats posed by a changing world to our goals of establishing standards of patient care, research, and the flexible training of the next generation. Images PMID:8229023

  19. New laser technologies in the clinic of neurosurgery

    NASA Astrophysics Data System (ADS)

    Stupak, V. V.; Fomichev, N. G.; Tsvetovsky, S. B.; Dmitriev, A. B.; Kobosev, V. V.; Bagaev, S. N.; Mayorov, A. P.; Struts, S. G.

    2005-08-01

    In report summarized more then 10 experience of authors in Novosibirsk Traumatology and orthopedics research institute Neurosurgery clinic on usage of laser technologies in treatment of central nervous system tumors. On the basis of ND-YAG laser application original technologies have been developed and used in surgical treatment of patients with various neurosurgical pathology and protected by 8 Patents of the Russian Federation. 427 patients were operated on with the use of YAG:Nd3+ laser. Out of them 152 patients had extracerebral tumors of various volume and localization, 135 patients - spinal cord tumors, 74 patients - a pathology of cerebrospinal transition (Amold-Chiari syndrome of 1-2 types), and 66 patients - intramedullary tumors of deep localization. Results showed good results of laser technologies usage for central nervous system tumors removal.

  20. [Intraoperative monitoring of oxygen tissue pressure: Applications in vascular neurosurgery].

    PubMed

    Arikan, Fuat; Vilalta, Jordi; Torne, Ramon; Chocron, Ivette; Rodriguez-Tesouro, Ana; Sahuquillo, Juan

    2014-01-01

    Ischemic lesions related to surgical procedures are a major cause of postoperative morbidity in patients with cerebral vascular disease. There are different systems of neuromonitoring to detect intraoperative ischemic events, including intraoperative monitoring of oxygen tissue pressure (PtiO2). The aim of this article was to describe, through the discussion of 4 cases, the usefulness of intraoperative PtiO2 monitoring during vascular neurosurgery. In presenting these cases, we demonstrate that monitoring PtiO2 is a reliable way to detect early ischemic events during surgical procedures. Continuous monitoring of PtiO2 in an area at risk allows the surgeon to resolve the cause of the ischemic event before it evolves to an established cerebral infarction. PMID:24934513

  1. High functional diversity stimulates diversification in experimental microbial communities

    PubMed Central

    Jousset, Alexandre; Eisenhauer, Nico; Merker, Monika; Mouquet, Nicolas; Scheu, Stefan

    2016-01-01

    There is a growing awareness that biodiversity not only drives ecosystem services but also affects evolutionary dynamics. However, different theories predict contrasting outcomes on when do evolutionary processes occur within a context of competition. We tested whether functional diversity can explain diversification patterns. We tracked the survival and diversification of a focal bacterial species (Pseudomonas fluorescens) growing in bacterial communities of variable diversity and composition. We found that high functional diversity reduced the fitness of the focal species and, at the same time, fostered its diversification. This pattern was linked to resource competition: High diversity increased competition on a portion of the resources while leaving most underexploited. The evolved phenotypes of the focal species showed a better use of underexploited resources, albeit at a cost of lower overall growth rates. As a result, diversification alleviated the impact of competition on the fitness of the focal species. We conclude that biodiversity can stimulate evolutionary diversification, provided that sufficient alternative niches are available. PMID:27386573

  2. High functional diversity stimulates diversification in experimental microbial communities.

    PubMed

    Jousset, Alexandre; Eisenhauer, Nico; Merker, Monika; Mouquet, Nicolas; Scheu, Stefan

    2016-06-01

    There is a growing awareness that biodiversity not only drives ecosystem services but also affects evolutionary dynamics. However, different theories predict contrasting outcomes on when do evolutionary processes occur within a context of competition. We tested whether functional diversity can explain diversification patterns. We tracked the survival and diversification of a focal bacterial species (Pseudomonas fluorescens) growing in bacterial communities of variable diversity and composition. We found that high functional diversity reduced the fitness of the focal species and, at the same time, fostered its diversification. This pattern was linked to resource competition: High diversity increased competition on a portion of the resources while leaving most underexploited. The evolved phenotypes of the focal species showed a better use of underexploited resources, albeit at a cost of lower overall growth rates. As a result, diversification alleviated the impact of competition on the fitness of the focal species. We conclude that biodiversity can stimulate evolutionary diversification, provided that sufficient alternative niches are available. PMID:27386573

  3. [FRACTIONATED STEREOTACTIC RADIOSURGERY: A GAME CHANGER FOR NEUROSURGERY].

    PubMed

    Nissim, Ouzi; Spiegelmann, Roberto

    2016-05-01

    The article by Dr. Cohen-Inbar published in this issue of Harefuah is a timely review that brings to the general medical community the recent important developments in the field of radiosurgery--the evolution of multi-session radiosurgery [or "FSR", standing for Fractionated Stereotactic Radiation]. Radiosurgery and FSR continue to have a tremendous impact on modern neurosurgery. Sharing sub-millimetric accuracy in radiation delivery made possible by real-time-imaging positioning, frameless single and multisession radiosurgery have become two faces of a therapeutic technique with wide application in the field of intracranial pathology. Blending dose fractionation with delivery precision, FSR is a hybrid tool that can be implemented safely and effectively for practically any intra-cranial pathology without restrictions of volume or location. Dr. Cohen Inbar reviews the available data regarding doses, fractionation schemes, and results for the different pathologies in which FSR is being increasingly applied. FSR, as single-dose radiosurgery since the late 1980s, has changed the practice of neurosurgery. Radical microsorgical tumor removal at any cost in demanding intracranial locations has been replaced by upfront conservative volume-reduction surgery, leaving the more complicated part of those tumors to safer elimination by precise irradiation in single or multiple sessions. In Israel, further to the first unit operative since 1993 at the Sheba Medical Center, 3 new active LINAC based treatment sites have been added in recent years, with facilities either planned or under construction in the remaining major medical centers with neurosurgical and radiotherapy resources. They are evidence of the central role this modality has captured in the management of intracranial pathology. PMID:27526561

  4. In vivo porcine training model for cranial neurosurgery.

    PubMed

    Regelsberger, Jan; Eicker, Sven; Siasios, Ioannis; Hänggi, Daniel; Kirsch, Matthias; Horn, Peter; Winkler, Peter; Signoretti, Stefano; Fountas, Kostas; Dufour, Henry; Barcia, Juan A; Sakowitz, Oliver; Westermaier, Thomas; Sabel, Michael; Heese, Oliver

    2015-01-01

    Supplemental education is desirable for neurosurgical training, and the use of human cadaver specimen and virtual reality models is routine. An in vivo porcine training model for cranial neurosurgery was introduced in 2005, and our recent experience with this unique model is outlined here. For the first time, porcine anatomy is illustrated with particular respect to neurosurgical procedures. The pros and cons of this model are described. The aim of the course was to set up a laboratory scenery imitating an almost realistic operating room in which anatomy of the brain and neurosurgical techniques in a mentored environment free from time constraints could be trained. Learning objectives of the course were to learn about the microsurgical techniques in cranial neurosurgery and the management of complications. Participants were asked to evaluate the quality and utility of the programme via standardized questionnaires by a grading scale from A (best) to E (worst). In total, 154 residents have been trained on the porcine model to date. None of the participants regarded his own residency programme as structured. The bleeding and complication management (97%), the realistic laboratory set-up (89%) and the working environment (94%) were favoured by the vast majority of trainees and confirmed our previous findings. After finishing the course, the participants graded that their skills in bone drilling, dissecting the brain and preserving cerebral vessels under microscopic magnification had improved to level A and B. In vivo hands-on courses, fully equipped with microsurgical instruments, offer an outstanding training opportunity in which bleeding management on a pulsating, vital brain represents a unique training approach. Our results have shown that education programmes still lack practical training facilities in which in vivo models may act as a complementary approach in surgical training. PMID:25240530

  5. Experimental studies on islets isolation, purification and function in rats.

    PubMed

    Pang, Xinlu; Xue, Wujun; Feng, Xinshun; Tian, Xiaohui; Teng, Yan; Ding, Xiaoming; Pan, Xiaoming; Guo, Qi; He, Xiaoli

    2015-01-01

    To develop a simple and effective method of islet isolation and purification in rats. Collagenase P was injected into pancreatic duct followed by incubation in water bath to digest the pancreas and isolate islet, then discontinuous gravity gradient purification was used to purify the islet. The purified islets were identified by dithizone staining. The viability of islets was assessed by fluorescence staining of acridine orange (AO) and propidium iodide (PI). The function of purified islets was determined by glucose-stimulated insulin release test and transplantation of rat with streptozocin-induced diabetes. 738±193 islets were recovered after purification. The average purity was 77±13%, the viability of islets was more than 95%. When inspected by glucose stimulation, the secreted insulin concentration was 24.31±5.47 mIU/L when stimulated by low concentration glucose and 37.62±4.29 mIU/L by high concentration glucose. There was significant difference between the two phases (P<0.05). The blood sugar concentration recovered to normal level after two days in the animals with islet transplantation. In conclusion, islets can be procured with good function and shape by using the method of injecting collagenase into pancreatic duct followed by incubation in water bath and purification using discontinuous gravity gradient. PMID:26885021

  6. Experimental studies on islets isolation, purification and function in rats

    PubMed Central

    Pang, Xinlu; Xue, Wujun; Feng, Xinshun; Tian, Xiaohui; Teng, Yan; Ding, Xiaoming; Pan, Xiaoming; Guo, Qi; He, Xiaoli

    2015-01-01

    To develop a simple and effective method of islet isolation and purification in rats. Collagenase P was injected into pancreatic duct followed by incubation in water bath to digest the pancreas and isolate islet, then discontinuous gravity gradient purification was used to purify the islet. The purified islets were identified by dithizone staining. The viability of islets was assessed by fluorescence staining of acridine orange (AO) and propidium iodide (PI). The function of purified islets was determined by glucose-stimulated insulin release test and transplantation of rat with streptozocin-induced diabetes. 738±193 islets were recovered after purification. The average purity was 77±13%, the viability of islets was more than 95%. When inspected by glucose stimulation, the secreted insulin concentration was 24.31±5.47 mIU/L when stimulated by low concentration glucose and 37.62±4.29 mIU/L by high concentration glucose. There was significant difference between the two phases (P<0.05). The blood sugar concentration recovered to normal level after two days in the animals with islet transplantation. In conclusion, islets can be procured with good function and shape by using the method of injecting collagenase into pancreatic duct followed by incubation in water bath and purification using discontinuous gravity gradient. PMID:26885021

  7. Experimental characterization of high speed centrifugal compressor aerodynamic forcing functions

    NASA Astrophysics Data System (ADS)

    Gallier, Kirk

    The most common and costly unexpected post-development gas turbine engine reliability issue is blade failure due to High Cycle Fatigue (HCF). HCF in centrifugal compressors is a coupled nonlinear fluid-structure problem for which understanding of the phenomenological root causes is incomplete. The complex physics of this problem provides significant challenges for Computational Fluid Dynamics (CFD) techniques. Furthermore, the available literature fails to address the flow field associated with the diffuser potential field, a primary cause of forced impeller vibration. Because of the serious nature of HCF, the inadequacy of current design approaches to predict HCF, and the fundamental lack of benchmark experiments to advance the design practices, there exists a need to build a database of information specific to the nature of the diffuser generated forcing function as a foundation for understanding flow induced blade vibratory failure. The specific aim of this research is to address the fundamental nature of the unsteady aerodynamic interaction phenomena inherent in high-speed centrifugal compressors wherein the impeller exit flow field is dynamically modulated by the vaned diffuser potential field or shock structure. The understanding of this unsteady aerodynamic interaction is fundamental to characterizing the impeller forcing function. Unsteady static pressure measurement at several radial and circumferential locations in the vaneless space offer a depiction of pressure field radial decay, circumferential variation and temporal fluctuation. These pressure measurements are coupled with high density, full field measurement of the velocity field within the diffuser vaneless space at multiple spanwise positions. The velocity field and unsteady pressure field are shown to be intimately linked. A strong momentum gradient exiting the impeller is shown to extend well across the vaneless space and interact with the diffuser vane leading edge. The deterministic unsteady

  8. Experimental and first-principles characterization of functionalized magnetic nanoparticles.

    PubMed

    Antipas, Georgios S E; Statharas, Eleftherios; Tserotas, Philippos; Papadopoulos, Nikolaos; Hristoforou, E

    2013-06-24

    Magnetic iron oxide nanoparticles synthesized by coprecipitation and thermal decomposition yield largely monodisperse size distributions. The diameters of the coprecipitated particles measured by X-ray diffraction and transmission electron microscopy are between approximately 9 and 15 nm, whereas the diameters of thermally decomposed particles are in the range of 8 to 10 nm. Coprecipitated particles are indexed as magnetite-rich and thermally decomposed particles as maghemite-rich; however, both methods produce a mixture of magnetite and maghemite. Fourier transform IR spectra reveal that the nanoparticles are coated with at least two layers of oleic acid (OA) surfactant. The inner layer is postulated to be chemically adsorbed on the nanoparticle surface whereas the rest of the OA is physically adsorbed, as indicated by carboxyl O-H stretching modes above 3400 cm(-1). Differential thermal analysis (DTA) results indicate a double-stepped weight loss process, the lower-temperature step of which is assigned to condensation due to physically adsorbed or low-energy bonded OA moieties. Density functional calculations of Fe-O clusters, the inverse spinel cell, and isolated OA, as well as OA in bidentate linkage with ferrous and ferric atoms, suggest that the higher-temperature DTA stage could be further broken down into two regions: one in which condensation is due ferrous/ferrous- and/or ferrous/ferric-OA and the other due to condensation from ferrous/ferric- and ferric/ferric-OA complexes. The latter appear to form bonds with the OA carbonyl group of energy up to fivefold that of the bond formed by the ferrous/ferrous pairs. Molecular orbital populations indicate that such increased stability of the ferric/ferric pair is due to the contribution of the low-lying Fe(3+) t(2g) states into four bonding orbitals between -0.623 and -0.410 a.u. PMID:23649714

  9. Uterine glands: development, function and experimental model systems.

    PubMed

    Cooke, Paul S; Spencer, Thomas E; Bartol, Frank F; Hayashi, Kanako

    2013-09-01

    Development of uterine glands (adenogenesis) in mammals typically begins during the early post-natal period and involves budding of nascent glands from the luminal epithelium and extensive cell proliferation in these structures as they grow into the surrounding stroma, elongate and mature. Uterine glands are essential for pregnancy, as demonstrated by the infertility that results from inhibiting the development of these glands through gene mutation or epigenetic strategies. Several genes, including forkhead box A2, beta-catenin and members of the Wnt and Hox gene families, are implicated in uterine gland development. Progestins inhibit uterine epithelial proliferation, and this has been employed as a strategy to develop a model in which progestin treatment of ewes for 8 weeks from birth produces infertile adults lacking uterine glands. More recently, mouse models have been developed in which neonatal progestin treatment was used to permanently inhibit adenogenesis and adult fertility. These studies revealed a narrow and well-defined window in which progestin treatments induced permanent infertility by impairing neonatal gland development and establishing endometrial changes that result in implantation defects. These model systems are being utilized to better understand the molecular mechanisms underlying uterine adenogenesis and endometrial function. The ability of neonatal progestin treatment in sheep and mice to produce infertility suggests that an approach of this kind may provide a contraceptive strategy with application in other species. Recent studies have defined the temporal patterns of adenogenesis in uteri of neonatal and juvenile dogs and work is underway to determine whether neonatal progestin or other steroid hormone treatments might be a viable contraceptive approach in this species. PMID:23619340

  10. Uterine glands: development, function and experimental model systems

    PubMed Central

    Cooke, Paul S.; Spencer, Thomas E.; Bartol, Frank F.; Hayashi, Kanako

    2013-01-01

    Development of uterine glands (adenogenesis) in mammals typically begins during the early post-natal period and involves budding of nascent glands from the luminal epithelium and extensive cell proliferation in these structures as they grow into the surrounding stroma, elongate and mature. Uterine glands are essential for pregnancy, as demonstrated by the infertility that results from inhibiting the development of these glands through gene mutation or epigenetic strategies. Several genes, including forkhead box A2, beta-catenin and members of the Wnt and Hox gene families, are implicated in uterine gland development. Progestins inhibit uterine epithelial proliferation, and this has been employed as a strategy to develop a model in which progestin treatment of ewes for 8 weeks from birth produces infertile adults lacking uterine glands. More recently, mouse models have been developed in which neonatal progestin treatment was used to permanently inhibit adenogenesis and adult fertility. These studies revealed a narrow and well-defined window in which progestin treatments induced permanent infertility by impairing neonatal gland development and establishing endometrial changes that result in implantation defects. These model systems are being utilized to better understand the molecular mechanisms underlying uterine adenogenesis and endometrial function. The ability of neonatal progestin treatment in sheep and mice to produce infertility suggests that an approach of this kind may provide a contraceptive strategy with application in other species. Recent studies have defined the temporal patterns of adenogenesis in uteri of neonatal and juvenile dogs and work is underway to determine whether neonatal progestin or other steroid hormone treatments might be a viable contraceptive approach in this species. PMID:23619340

  11. Biases in the Experimental Annotations of Protein Function and Their Effect on Our Understanding of Protein Function Space

    PubMed Central

    Schnoes, Alexandra M.; Ream, David C.; Thorman, Alexander W.; Babbitt, Patricia C.; Friedberg, Iddo

    2013-01-01

    The ongoing functional annotation of proteins relies upon the work of curators to capture experimental findings from scientific literature and apply them to protein sequence and structure data. However, with the increasing use of high-throughput experimental assays, a small number of experimental studies dominate the functional protein annotations collected in databases. Here, we investigate just how prevalent is the “few articles - many proteins” phenomenon. We examine the experimentally validated annotation of proteins provided by several groups in the GO Consortium, and show that the distribution of proteins per published study is exponential, with 0.14% of articles providing the source of annotations for 25% of the proteins in the UniProt-GOA compilation. Since each of the dominant articles describes the use of an assay that can find only one function or a small group of functions, this leads to substantial biases in what we know about the function of many proteins. Mass-spectrometry, microscopy and RNAi experiments dominate high throughput experiments. Consequently, the functional information derived from these experiments is mostly of the subcellular location of proteins, and of the participation of proteins in embryonic developmental pathways. For some organisms, the information provided by different studies overlap by a large amount. We also show that the information provided by high throughput experiments is less specific than those provided by low throughput experiments. Given the experimental techniques available, certain biases in protein function annotation due to high-throughput experiments are unavoidable. Knowing that these biases exist and understanding their characteristics and extent is important for database curators, developers of function annotation programs, and anyone who uses protein function annotation data to plan experiments. PMID:23737737

  12. History and current state of neurosurgery at the Medical University of South Carolina.

    PubMed

    Krishna, Vibhor; Rauf, Yasmeen; Patel, Sunil; Glazier, Steve; Perot, Phanor; Ellegala, Dilantha B

    2011-07-01

    We review the development of neurosurgery at the Medical University of South Carolina (MUSC) and the emergence of MUSC as a leading academic neurosurgical center in South Carolina. Historical records from the Waring Historical Library were studied, former and current faculty members were interviewed, and the personal records of Dr Phanor J Perot were examined. Dr Frederick E Kredel was the first to perform cerebral revascularization in stroke patients using omental flaps and the first to culture glioma cells in artificial media. The MUSC Neurosurgery residency program was established in 1964 by its first formally trained neurosurgeon, Julian Youmans, MD. The first graduate of the program, Dr Russell Travis, went on to become the President of the American Association of Neurological Surgeons. In 1968, the longest serving chairman, Dr Perot, joined the department and conducted significant research in spinal cord injury, receiving a continuous, 20-year award from the National Institute of Neurological Disorders and Stroke. A major change in the neurosurgery program occurred in 2004 when Dr Sunil Patel accepted the chairmanship. He integrated neurosurgery, neurology, and basic neuroscience departments into a comprehensive Department of Neurosciences to provide integrated clinical care. This department now ranks second in the country in National Institutes of Health research funding. Recently, the Center for Global Health and Global Neurosurgery was established with a vision of caring for patients beyond national borders. Neurosurgery at MUSC has been influenced by Drs Kredel and Perot and the current leadership is moving forward with a uniquely integrated department with novel areas such as global neurosurgery. PMID:21368698

  13. FUNCTIONAL ASPECTS OF DEVELOPMENTAL TOXICITY OF POLYHALOGENATED AROMATIC HYDROCARBONS IN EXPERIMENTAL ANIMALS AND HUMAN INFANTS

    EPA Science Inventory

    A scientific evaluation was made of functional aspects of developmental toxicity of polychlorinated biphenyls (PCBs)-dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) in experimental animals and in human infants. ersistent neurobehavioral, reproductive, and endocrine alteration...

  14. Neurosurgery value and quality in the context of the Affordable Care Act: a policy perspective.

    PubMed

    Menger, Richard P; Guthikonda, Bharat; Storey, Christopher M; Nanda, Anil; McGirt, Matthew; Asher, Anthony

    2015-12-01

    Neurosurgeons provide direct individualized care to patients. However, the majority of regulations affecting the relative value of patient-related care are drafted by policy experts whose focus is typically system- and population-based. A central, prospectively gathered, national outcomes-related database serves as neurosurgery's best opportunity to bring patient-centered outcomes to the policy arena. In this study the authors analyze the impact of the Affordable Care Act (ACA) on the determination of quality and value in neurosurgery care through the scope, language, and terminology of policy experts. The methods by which the ACA came into law and the subsequent quality implications this legislation has for neurosurgery will be discussed. The necessity of neurosurgical patient-oriented clinical registries will be discussed in the context of imminent and dramatic reforms related to medical cost containment. In the policy debate moving forward, the strength of neurosurgery's argument will rest on data, unity, and proactiveness. The National Neurosurgery Quality and Outcomes Database (N(2)QOD) allows neurosurgeons to generate objective data on specialty-specific value and quality determinations; it allows neurosurgeons to bring the patient-physician interaction to the policy debate. PMID:26621419

  15. Robotics in neurosurgery: state of the art and future technological challenges.

    PubMed

    Zamorano, L; Li, Q; Jain, S; Kaur, G

    2004-06-01

    The use of robotic technologies to assist surgeons was conceptually described almost thirty years ago but has only recently become feasible. In Neurosurgery, medical robots have been applied to neurosurgery for over 19 years. Nevertheless this field remains unknown to most neurosurgeons. The intrinsic characteristics of robots, such as high precision, repeatability and endurance make them ideal surgeon's assistants. Unfortunately, limitations in the current available systems make its use limited to very few centers in the world. During the last decade, important efforts have been made between academic and industry partnerships to develop robots suitable for use in the operating room environment. Although some applications have been successful in areas of laparoscopic surgery and orthopaedics, Neurosurgery has presented a major challenge due to the eloquence of the surrounding anatomy. This review focuses on the application of medical robotics in neurosurgery. The paper begins with an overview of the development of the medical robotics, followed by the current clinical applications in neurosurgery and an analysis of current limitations. We discuss robotic applications based in our own experience in the field. Next, we discuss the technological challenges and research areas to overcome those limitations, including some of our current research approaches for future progress in the field. PMID:17520593

  16. Experimental evidence for strong stabilizing forces at high functional diversity of aquatic microbial communities.

    PubMed

    Carrara, Francesco; Giometto, Andrea; Seymour, Mathew; Rinaldo, Andrea; Altermatt, Florian

    2015-05-01

    Unveiling the mechanisms that promote coexistence in biological communities is a fundamental problem in ecology. Stable coexistence of many species is commonly observed in natural communities. Most of these natural communities, however, are composed of species from multiple trophic and functional groups, while theory and experiments on coexistence have been focusing on functionally similar species. Here, we investigated how functional diversity affects the stability of species coexistence and productivity in multispecies communities by characterizing experimentally all pairwise species interactions in a pool of 11 species of eukaryotes (10 protists and one rotifer) belonging to three different functional groups. Species within the same functional group showed stronger competitive interactions compared to among-functional group interactions. This often led to competitive exclusion between species that had higher functional relatedness, but only at low levels of species richness. Communities with higher functional diversity resulted in increased species coexistence and community biomass production. Our experimental findings and the results of a stochastic model tailored to the experimental interaction matrix suggest the emergence of strong stabilizing forces when species from different functional groups interact in a homogeneous environment. By combining theoretical analysis with experiments we could also disentangle the relationship between species richness and functional diversity, showing that functional diversity per se is a crucial driver of productivity and stability in multispecies community. PMID:26236847

  17. Investigating the Scope of Resident Patient Care Handoffs within Neurosurgery

    PubMed Central

    Babu, Maya A.; Nahed, Brian V.; Heary, Robert F.

    2012-01-01

    Introduction Handoffs are defined as verbal and written communications during patient care transitions. With the passage of recent ACMGE work hour rules further limiting the hours interns can spend in the hospital, many fear that more handoffs will occur, putting patient safety at risk. The issue of handoffs has not been studied in the neurosurgical literature. Methods A validated, 20-question online-survey was sent to neurosurgical residents in all 98 accredited U.S. neurosurgery programs. Survey results were analyzed using tabulations. Results 449 surveys were completed yielding a 56% response rate. 63% of neurosurgical residents surveyed had not received formal instruction in what constitutes an effective handoff; 24% believe there is high to moderate variability among their co-residents in terms of the quality of the handoff provided; 55% experience three or more interruptions during handoffs on average. 90% of neurosurgical residents surveyed say that handoff most often occurs in a quiet, private area and 56% report a high level of comfort for knowing the potential acute, critical issues affecting a patient when receiving a handoff. Conclusions There needs to be more focused education devoted to learning effective patient-care handoffs in neurosurgical training programs. Increasingly, handing off a patient adequately and safely is becoming a required skill of residency. PMID:22848615

  18. Evaluation of a synergistically controlled semiautomatic trepanation system for neurosurgery.

    PubMed

    Follmann, Axel; Korff, Alexander; Furtjes, Tobias; Lauer, Wolfgang; Kunze, Sandra C; Schmieder, Kirsten; Radermacher, Klaus

    2010-01-01

    One of the most common procedures in neurosurgery is the trepanation of the skull. In this paper, a synergistically controlled handheld tool for trepanation is introduced. This instrument is envisioned to reduce problems of dural tears and wide cutting gaps by combining a soft tissue preserving saw with an automatic regulation of the cutting depth. Since usability and safety of the semi-automatic handheld device are of utmost importance, the complex interaction between the user and the system has been analyzed extensively. Based on prospective usability evaluation the user interaction design and the corresponding user-interface were developed. The compliance with the relevant factors effectiveness, efficiency, error tolerance, learnability and user satisfaction was measured in user-centered experiments to evaluate the usability of the semiautomatic trepanation system. The results confirm the user interaction design of the semiautomatic trepanation system and the corresponding safety strategy. The system seems to integrate itself smoothly into the existing workflow and keeps the surgeon aware of the process. PMID:21096797

  19. Using Electronic Noses to Detect Tumors During Neurosurgery

    NASA Technical Reports Server (NTRS)

    Homer, Margie L.; Ryan, Margaret A.; Lara, Liana M.; Kateb, Babak; Chen, Mike

    2008-01-01

    It has been proposed to develop special-purpose electronic noses and algorithms for processing the digitized outputs of the electronic noses for determining whether tissue exposed during neurosurgery is cancerous. At present, visual inspection by a surgeon is the only available intraoperative technique for detecting cancerous tissue. Implementation of the proposal would help to satisfy a desire, expressed by some neurosurgeons, for an intraoperative technique for determining whether all of a brain tumor has been removed. The electronic-nose technique could complement multimodal imaging techniques, which have also been proposed as means of detecting cancerous tissue. There are also other potential applications of the electronic-nose technique in general diagnosis of abnormal tissue. In preliminary experiments performed to assess the viability of the proposal, the problem of distinguishing between different types of cultured cells was substituted for the problem of distinguishing between normal and abnormal specimens of the same type of tissue. The figure presents data from one experiment, illustrating differences between patterns that could be used to distinguish between two types of cultured cancer cells. Further development can be expected to include studies directed toward answering questions concerning not only the possibility of distinguishing among various types of normal and abnormal tissue but also distinguishing between tissues of interest and other odorous substances that may be present in medical settings.

  20. Examining the Function of Problem Behavior in Fragile X Syndrome: Preliminary Experimental Analysis

    ERIC Educational Resources Information Center

    Langthorne, Paul; McGill, Peter; O'Reilly, Mark F.; Lang, Russell; Machalicek, Wendy; Chan, Jeffrey Michael; Rispoli, Mandy

    2011-01-01

    Fragile X syndrome is the most common inherited cause of intellectual and developmental disability. The influence of environmental variables on behaviors associated with the syndrome has received only scant attention. The current study explored the function served by problem behavior in fragile X syndrome by using experimental functional analysis…

  1. Effects of Physical Activity on Children's Executive Function: Contributions of Experimental Research on Aerobic Exercise

    ERIC Educational Resources Information Center

    Best, John R.

    2010-01-01

    Executive function refers to the cognitive processes necessary for goal-directed cognition and behavior, which develop across childhood and adolescence. Recent experimental research indicates that both acute and chronic aerobic exercise promote children's executive function. Furthermore, there is tentative evidence that not all forms of aerobic…

  2. Clinical Outcomes of Wulingsan Subtraction Decoction Treatment of Postoperative Brain Edema and Fever as a Complication of Glioma Neurosurgery

    PubMed Central

    Jin, Wei-rong; Zhang, Feng-e; Diao, Bao-zhong; Zhang, Yue-ying

    2016-01-01

    Objective. To evaluate the efficacy of Wulingsan subtraction (五苓散加减 WLSS) decoction in the treatment of postoperative brain edema and fever as a complication of glioma neurosurgery. Methods. This retrospective study was conducted at the Department of Neurosurgery of Liaocheng People's Hospital. Patients hospitalized between March 2011 and December 2014 were divided into three groups: Group A received WLSS oral liquid (50 mL), twice a day; Group B received an intravenous infusion of mannitol; and Group C received WLSS combined with mannitol (n = 30 patients per group). All patients were treated for 10 days continuously. Therapeutic efficacy was evaluated by measuring body temperature and indicators of renal function before and 3, 5, and 10 days after treatment. Results. Compared to the other two groups, significantly greater clinical efficacy was observed in the patients treated with mannitol (Group B; P < 0.05), although marked clinical efficacy was also observed over time in patients treated with WLSS (Group A). After 5 days, the quantifiable effects of the WLSS and mannitol combination group (Group C) were substantial (P < 0.05). The renal damage in Group B was more obvious after 5 days and 10 days. Conclusion. Compared with mannitol treatment alone, WLSS combined with mannitol induced a more rapid reduction in body temperature. Our findings suggest that patients should be started on mannitol for 3 days and then switched to WLSS to achieve obvious antipyretic effects and protect renal function. This method of treatment should be considered for clinical applications. PMID:27019661

  3. Practical guidelines for setting up neurosurgery skills training cadaver laboratory in India.

    PubMed

    Suri, Ashish; Roy, Tara Sankar; Lalwani, Sanjeev; Deo, Rama Chandra; Tripathi, Manjul; Dhingra, Renu; Bhardwaj, Daya Nand; Sharma, Bhawani Shankar

    2014-01-01

    Though the necessity of cadaver dissection is felt by the medical fraternity, and described as early as 600 BC, in India, there are no practical guidelines available in the world literature for setting up a basic cadaver dissection laboratory for neurosurgery skills training. Hands-on dissection practice on microscopic and endoscopic procedures is essential in technologically demanding modern neurosurgery training where ethical issues, cost constraints, medico-legal pitfalls, and resident duty time restrictions have resulted in lesser opportunities to learn. Collaboration of anatomy, forensic medicine, and neurosurgery is essential for development of a workflow of cadaver procurement, preservation, storage, dissection, and disposal along with setting up the guidelines for ethical and legal concerns. PMID:25033845

  4. [Recent progress in intravascular neurosurgery for the treatment of cerebrovascular disease].

    PubMed

    Hyodo, A; Harakuni, T; Shingaki, T; Tsurushima, H; Saito, A; Yoshii, Y

    2000-12-01

    With the recent advances in the devices and techniques in intravascular neurosurgery such as microcatheters or a digital subtraction angiography, intravascular neurosurgery plays an important role for the treatment of cerebrovascular disease. We describe here, a recent progress in intravascular neurosurgery for the treatment of cerebrovascular disease. As a treatment of cerebrovascular disease, we discuss the treatment of cerebral aneurysm using Guglielmi detachable coils (GDC), and the treatment of ischemic cerebrovascular disease such as the thrombolytic therapy for the acute embolic occlusion of the cerebral artery, and a percutaneous transluminal angioplasty (PTA) or a stenting for the stenotic lesion of the cerebral arteries. Embolization of the cerebral aneurysm using GDC is less invasive method compare to the standard neurosurgical clipping of aneurysm. So, recently it becomes one of standard methods of the treatment of cerebral aneurysm. Thrombolytic therapy, PTA and stenting also become an important treatment for the ischemic cerebrovascular disease. PMID:11464467

  5. Robotic System for MRI-Guided Stereotactic Neurosurgery

    PubMed Central

    Li, Gang; Cole, Gregory A.; Shang, Weijian; Harrington, Kevin; Camilo, Alex; Pilitsis, Julie G.; Fischer, Gregory S.

    2015-01-01

    Stereotaxy is a neurosurgical technique that can take several hours to reach a specific target, typically utilizing a mechanical frame and guided by preoperative imaging. An error in any one of the numerous steps or deviations of the target anatomy from the preoperative plan such as brain shift (up to 20 mm), may affect the targeting accuracy and thus the treatment effectiveness. Moreover, because the procedure is typically performed through a small burr hole opening in the skull that prevents tissue visualization, the intervention is basically “blind” for the operator with limited means of intraoperative confirmation that may result in reduced accuracy and safety. The presented system is intended to address the clinical needs for enhanced efficiency, accuracy, and safety of image-guided stereotactic neurosurgery for Deep Brain Stimulation (DBS) lead placement. The work describes a magnetic resonance imaging (MRI)-guided, robotically actuated stereotactic neural intervention system for deep brain stimulation procedure, which offers the potential of reducing procedure duration while improving targeting accuracy and enhancing safety. This is achieved through simultaneous robotic manipulation of the instrument and interactively updated in situ MRI guidance that enables visualization of the anatomy and interventional instrument. During simultaneous actuation and imaging, the system has demonstrated less than 15% signal-to-noise ratio (SNR) variation and less than 0.20% geometric distortion artifact without affecting the imaging usability to visualize and guide the procedure. Optical tracking and MRI phantom experiments streamline the clinical workflow of the prototype system, corroborating targeting accuracy with 3-axis root mean square error 1.38 ± 0.45 mm in tip position and 2.03 ± 0.58° in insertion angle. PMID:25376035

  6. Consensus on guidelines for stereotactic neurosurgery for psychiatric disorders

    PubMed Central

    Nuttin, Bart; Wu, Hemmings; Mayberg, Helen; Hariz, Marwan; Gabriëls, Loes; Galert, Thorsten; Merkel, Reinhard; Kubu, Cynthia; Vilela-Filho, Osvaldo; Matthews, Keith; Taira, Takaomi; Lozano, Andres M; Schechtmann, Gastón; Doshi, Paresh; Broggi, Giovanni; Régis, Jean; Alkhani, Ahmed; Sun, Bomin; Eljamel, Sam; Schulder, Michael; Kaplitt, Michael; Eskandar, Emad; Rezai, Ali; Krauss, Joachim K; Hilven, Paulien; Schuurman, Rick; Ruiz, Pedro; Chang, Jin Woo; Cosyns, Paul; Lipsman, Nir; Voges, Juergen; Cosgrove, Rees; Li, Yongjie; Schlaepfer, Thomas

    2014-01-01

    Background For patients with psychiatric illnesses remaining refractory to ‘standard’ therapies, neurosurgical procedures may be considered. Guidelines for safe and ethical conduct of such procedures have previously and independently been proposed by various local and regional expert groups. Methods To expand on these earlier documents, representative members of continental and international psychiatric and neurosurgical societies, joined efforts to further elaborate and adopt a pragmatic worldwide set of guidelines. These are intended to address a broad range of neuropsychiatric disorders, brain targets and neurosurgical techniques, taking into account cultural and social heterogeneities of healthcare environments. Findings The proposed consensus document highlights that, while stereotactic ablative procedures such as cingulotomy and capsulotomy for depression and obsessive-compulsive disorder are considered ‘established’ in some countries, they still lack level I evidence. Further, it is noted that deep brain stimulation in any brain target hitherto tried, and for any psychiatric or behavioural disorder, still remains at an investigational stage. Researchers are encouraged to design randomised controlled trials, based on scientific and data-driven rationales for disease and brain target selection. Experienced multidisciplinary teams are a mandatory requirement for the safe and ethical conduct of any psychiatric neurosurgery, ensuring documented refractoriness of patients, proper consent procedures that respect patient's capacity and autonomy, multifaceted preoperative as well as postoperative long-term follow-up evaluation, and reporting of effects and side effects for all patients. Interpretation This consensus document on ethical and scientific conduct of psychiatric surgery worldwide is designed to enhance patient safety. PMID:24444853

  7. Simulation of brain tumor resection in image-guided neurosurgery

    NASA Astrophysics Data System (ADS)

    Fan, Xiaoyao; Ji, Songbai; Fontaine, Kathryn; Hartov, Alex; Roberts, David; Paulsen, Keith

    2011-03-01

    Preoperative magnetic resonance images are typically used for neuronavigation in image-guided neurosurgery. However, intraoperative brain deformation (e.g., as a result of gravitation, loss of cerebrospinal fluid, retraction, resection, etc.) significantly degrades the accuracy in image guidance, and must be compensated for in order to maintain sufficient accuracy for navigation. Biomechanical finite element models are effective techniques that assimilate intraoperative data and compute whole-brain deformation from which to generate model-updated MR images (uMR) to improve accuracy in intraoperative guidance. To date, most studies have focused on early surgical stages (i.e., after craniotomy and durotomy), whereas simulation of more complex events at later surgical stages has remained to be a challenge using biomechanical models. We have developed a method to simulate partial or complete tumor resection that incorporates intraoperative volumetric ultrasound (US) and stereovision (SV), and the resulting whole-brain deformation was used to generate uMR. The 3D ultrasound and stereovision systems are complimentary to each other because they capture features deeper in the brain beneath the craniotomy and at the exposed cortical surface, respectively. In this paper, we illustrate the application of the proposed method to simulate brain tumor resection at three temporally distinct surgical stages throughout a clinical surgery case using sparse displacement data obtained from both the US and SV systems. We demonstrate that our technique is feasible to produce uMR that agrees well with intraoperative US and SV images after dural opening, after partial tumor resection, and after complete tumor resection. Currently, the computational cost to simulate tumor resection can be up to 30 min because of the need for re-meshing and the trial-and-error approach to refine the amount of tissue resection. However, this approach introduces minimal interruption to the surgical workflow

  8. Smartphones in remote medicine and daily neurosurgery: The Sabah update

    PubMed Central

    Perumall, Vinodh Vayara; Sellamuthu, Pulivendhan; Harun, Rahmat; Zenian, Mohd Sofan

    2015-01-01

    Introduction: Healthcare costs continue to rise every day as the demand outgrows the supply of surgeons. The application of telephone consultation for immediate management is needed as most neurosurgeons are technology orientated. This enables a specialist at a remote mobile site to receive the necessary information and reduce transmission time, from the second the patient is seen till the management is obtained. Materials and Methods: We conducted a survey on smartphone ownership among doctors and gathered cases that needed neurosurgical input from 1st November 2012 till 30th April 2013 from all 24 district hospitals in Sabah, Malaysia. Results: The percentage of smartphone ownership among doctors surveyed and usage of it for remote and daily medicine at various departments at Queen Elizabeth Hospital, Kota Kinabalu, which shows at least 90% smartphone ownership and proves 100% ownership of cross-platform instant messaging applications and its usage for remote and daily medicine. It also proves to be a more popular mode of referral compared to “teleconsultation” (TC). Discussion: In Sabah, the TC service is used for remote medical consultation and only available at four hospitals. The sender needs direct access to a computer with the TC software, and it causes delay whereas doctors using smartphones will just need to discuss the case on the spot and obtain the appropriate management within minutes. Smartphone usage is also important in daily neurosurgery especially at the department level to promote efficient communication, organization, and interaction between all the staff. As for the department's administrative sector, it is useful to notify if anyone is on leave, attending courses or even meetings as the shortage can be avoided, and redistribution easily done. It also allows us to transfer simple intra-departmental data at any time, and any place whenever required. Conclusion: With all the given fact, it is clear that a day without utilizing this service

  9. Sensors management in robotic neurosurgery: the ROBOCAST project.

    PubMed

    Vaccarella, Alberto; Comparetti, Mirko Daniele; Enquobahrie, Andinet; Ferrigno, Giancarlo; De Momi, Elena

    2011-01-01

    Robot and computer-aided surgery platforms bring a variety of sensors into the operating room. These sensors generate information to be synchronized and merged for improving the accuracy and the safety of the surgical procedure for both patients and operators. In this paper, we present our work on the development of a sensor management architecture that is used is to gather and fuse data from localization systems, such as optical and electromagnetic trackers and ultrasound imaging devices. The architecture follows a modular client-server approach and was implemented within the EU-funded project ROBOCAST (FP7 ICT 215190). Furthermore it is based on very well-maintained open-source libraries such as OpenCV and Image-Guided Surgery Toolkit (IGSTK), which are supported from a worldwide community of developers and allow a significant reduction of software costs. We conducted experiments to evaluate the performance of the sensor manager module. We computed the response time needed for a client to receive tracking data or video images, and the time lag between synchronous acquisition with an optical tracker and ultrasound machine. Results showed a median delay of 1.9 ms for a client request of tracking data and about 40 ms for US images; these values are compatible with the data generation rate (20-30 Hz for tracking system and 25 fps for PAL video). Simultaneous acquisitions have been performed with an optical tracking system and US imaging device: data was aligned according to the timestamp associated with each sample and the delay was estimated with a cross-correlation study. A median value of 230 ms delay was calculated showing that realtime 3D reconstruction is not feasible (an offline temporal calibration is needed), although a slow exploration is possible. In conclusion, as far as asleep patient neurosurgery is concerned, the proposed setup is indeed useful for registration error correction because the brain shift occurs with a time constant of few tens of minutes

  10. Versatile utilization of real-time intraoperative contrast-enhanced ultrasound in cranial neurosurgery: technical note and retrospective case series.

    PubMed

    Lekht, Ilya; Brauner, Noah; Bakhsheshian, Joshua; Chang, Ki-Eun; Gulati, Mittul; Shiroishi, Mark S; Grant, Edward G; Christian, Eisha; Zada, Gabriel

    2016-03-01

    OBJECTIVE Intraoperative contrast-enhanced ultrasound (iCEUS) offers dynamic imaging and provides functional data in real time. However, no standardized protocols or validated quantitative data exist to guide its routine use in neurosurgery. The authors aimed to provide further clinical data on the versatile application of iCEUS through a technical note and illustrative case series. METHODS Five patients undergoing craniotomies for suspected tumors were included. iCEUS was performed using a contrast agent composed of lipid shell microspheres enclosing perflutren (octafluoropropane) gas. Perfusion data were acquired through a time-intensity curve analysis protocol obtained using iCEUS prior to biopsy and/or resection of all lesions. RESULTS Three primary tumors (gemistocytic astrocytoma, glioblastoma multiforme, and meningioma), 1 metastatic lesion (melanoma), and 1 tumefactive demyelinating lesion (multiple sclerosis) were assessed using real-time iCEUS. No intraoperative complications occurred following multiple administrations of contrast agent in all cases. In all neoplastic cases, iCEUS replicated enhancement patterns observed on preoperative Gd-enhanced MRI, facilitated safe tumor debulking by differentiating neoplastic tissue from normal brain parenchyma, and helped identify arterial feeders and draining veins in and around the surgical cavity. Intraoperative CEUS was also useful in guiding a successful intraoperative needle biopsy of a cerebellar tumefactive demyelinating lesion obtained during real-time perfusion analysis. CONCLUSIONS Intraoperative CEUS has potential for safe, real-time, dynamic contrast-based imaging for routine use in neurooncological surgery and image-guided biopsy. Intraoperative CEUS eliminates the effect of anatomical distortions associated with standard neuronavigation and provides quantitative perfusion data in real time, which may hold major implications for intraoperative diagnosis, tissue differentiation, and quantification of

  11. Experimental Study of Level Density and {gamma}-strength Functions from Compound Nuclear Reactions

    SciTech Connect

    Voinov, A. V.; Grimes, S. M.; Brune, C. R.; Massey, T. N.; Schiller, A.; Guttormsen, M.; Siem, S.

    2008-04-17

    The current status of experimental study of level density and {gamma}-strength functions is reviewed. Three experimental techniques are used. These are measurements of particle evaporation spectra from compound nuclear reactions, the measurements of particle-{gamma} coincidences from inelastic scattering and pick-up reactions and the method of two-step {gamma}-cascades following neutron/proton radiative capture. Recent experimental data on level densities from neutron evaporation spectra are shown. The first results on the cascade {gamma}-spectrum from the {sup 59}Co(p,2{gamma}){sup 60}Ni reaction are presented.

  12. The rewards of pediatric neurosurgery: presidential address: twenty-ninth annual meeting of the International Society for Pediatric Neurosurgery, October 18, 2011, Goa, India.

    PubMed

    Steinbok, Paul

    2012-09-01

    The author relates how he ended up somewhat unexpectedly as a pediatric neurosurgeon and how fortunate he feels to have become a pediatric neurosurgeon. He reflects on his life and on the importance of trying to do one's best. He comments about the importance of listening, empathizing, and being compassionate as characteristics of the pediatric neurosurgeon and notes that by trying one's best to be a good pediatric neurosurgeon one adopts more of these characteristics by learning from patients and their parents. He discusses the many ways in which the practice of pediatric neurosurgery and his involvement in the International Society for Pediatric Neurosurgery have created meaning in his life, which has led to a feeling of happiness and fulfillment. PMID:22872238

  13. Reconstruction of the unknown optimization cost functions from experimental recordings during static multi-finger prehension.

    PubMed

    Niu, Xun; Terekhov, Alexander V; Latash, Mark L; Zatsiorsky, Vladimir M

    2012-04-01

    The goal of the research is to reconstruct the unknown cost (objective) function(s) presumably used by the neural controller for sharing the total force among individual fingers in multifinger prehension. The cost function was determined from experimental data by applying the recently developed Analytical Inverse Optimization (ANIO) method (Terekhov et al. 2010). The core of the ANIO method is the Theorem of Uniqueness that specifies conditions for unique (with some restrictions) estimation of the objective functions. In the experiment, subjects (n = 8) grasped an instrumented handle and maintained it at rest in the air with various external torques, loads, and target grasping forces applied to the object. The experimental data recorded from 80 trials showed a tendency to lie on a 2-dimensional hyperplane in the 4-dimensional finger-force space. Because the constraints in each trial were different, such a propensity is a manifestation of a neural mechanism (not the task mechanics). In agreement with the Lagrange principle for the inverse optimization, the plane of experimental observations was close to the plane resulting from the direct optimization. The latter plane was determined using the ANIO method. The unknown cost function was reconstructed successfully for each performer, as well as for the group data. The cost functions were found to be quadratic with nonzero linear terms. The cost functions obtained with the ANIO method yielded more accurate results than other optimization methods. The ANIO method has an evident potential for addressing the problem of optimization in motor control. PMID:22104742

  14. Experimental investigations of the scanning functions of galvanometer-based scanners with applications in OCT.

    PubMed

    Duma, Virgil-Florin; Lee, Kye-sung; Meemon, Panomsak; Rolland, Jannick P

    2011-10-10

    We analyze the three most common profiles of scanning functions for galvanometer-based scanners (GSs): the sawtooth, triangular and sinusoidal functions. They are determined experimentally with regard to the scan parameters of the input signal (i.e., frequency and amplitude). We study the differences of the output function of the GS measured as the positional error of the oscillatory mirror from the ideal function given by the input signal of the device. The limits in achieving the different types of scanning functions in terms of duty cycle and linearity are determined experimentally for the possible range of scan parameters. Of particular importance are the preservation of an imposed duty cycle and profile for the sawtooth function, the quantification of the linearity for the sinusoidal function, and the effective duty cycle for the triangular, as well as for the other functions. The range of scan amplitudes for which the stability of the oscillatory regime of the galvo mirror is stable for different frequencies is also highlighted. While the use of the device in certain scanning regimes is studied, certain rules of thumb are deduced to make the best out of the galvoscanner. Finally, the three types of scanning functions are tested with a Fourier domain optical coherence tomography (FD OCT) setup and the conclusions of the study are demonstrated in an imaging application by correlating the determined limits of the scanning regimes with the requirements of OCT. PMID:22015369

  15. Fedor Krause: the first systematic use of X-rays in neurosurgery.

    PubMed

    Elhadi, Ali M; Kalb, Samuel; Martirosyan, Nikolay L; Agrawal, Abhishek; Preul, Mark C

    2012-08-01

    Within a few months of Wilhelm Conrad Röntgen's discovery of x-rays in 1895, Fedor Krause acquired an x-ray apparatus and began to use it in his daily interactions with patients and for diagnosis. He was the first neurosurgeon to use x-rays methodically and systematically. In 1908 Krause published the first volume of text on neurosurgery, Chirurgie des Gehirns und Rückenmarks (Surgery of the Brain and Spinal Cord), which was translated into English in 1909. The second volume followed in 1911. This was the first published multivolume text totally devoted to neurosurgery. Although Krause excelled in and promoted neurosurgery, he believed that surgeons should excel at general surgery. Importantly, Krause was inclined to adopt technology that he believed could be helpful in surgery. His 1908 text was the first neurosurgical text to contain a specific chapter on x-rays ("Radiographie") that showed roentgenograms of neurosurgical procedures and pathology. After the revolutionary discovery of x-rays by Röntgen, many prominent neurosurgeons seemed pessimistic about the use of x-rays for anything more than trauma or fractures. Krause immediately seized on its use to guide and monitor ventricular drainage and especially for the diagnosis of tumors of the skull base. The x-ray images contained in Krause's "Radiographie" chapter provide a seminal view into the adoption of new technology and the development of neurosurgical technique and are part of neurosurgery's heritage. PMID:22853835

  16. The Mathematics of Three N-Localizers Used Together for Stereotactic Neurosurgery

    PubMed Central

    2015-01-01

    The N-localizer enjoys widespread use in image-guided stereotactic neurosurgery and radiosurgery. This article derives the mathematical equations that are used with three N-localizers and provides analogies, explanations, and appendices in order to promote a deeper understanding of the mathematical principles that govern the N-localizer. PMID:26594605

  17. The contributions of W.D. Stevenson to the development of neurosurgery in Atlantic Canada.

    PubMed

    Mukhida, K; Mendez, I

    1999-08-01

    The establishment of a neurosurgical department in Halifax in January 1948 marked the beginnings of the first dedicated neurosurgical service in Atlantic Canada. The development of neurosurgery in Halifax occurred in a receptive place and time. The Victoria General Hospital, the region's largest tertiary care centre, and the Dalhousie University Faculty of Medicine were in a period of growth associated with medical specialization and departmentalization, changes inspired in part by the Flexner Report of 1910. Atlantic Canadians during this period were increasingly looking to specialists for their medical care. Although this social environment encouraged the establishment of surgical specialty services, the development of neurosurgery in Halifax, as in other parts of Canada, was closely associated with the efforts of individual neurosurgeons, such as William D. Stevenson. After training with Kenneth G. McKenzie in Toronto, Stevenson was recruited to Halifax and established the first neurosurgical department in Atlantic Canada. From the outset and over his twenty-six years as Department Head at the Victoria General Hospital and Dalhousie University, Stevenson worked to maintain the department's commitment to clinical practice, medical education, and research. Although Stevenson single-handedly ran the service for several years after its inception, by the time of his retirement in 1974 the neurosurgery department had grown to include five attending staff surgeons who performed over two thousand procedures each year. This paper highlights the importance of Stevenson's contributions to the development of neurosurgery in Atlantic Canada within the context of the social and medical environment of the region. PMID:10451747

  18. The sitting position in neurosurgery: a critical appraisal.

    PubMed

    Porter, J M; Pidgeon, C; Cunningham, A J

    1999-01-01

    The potential for serious complications after venous air embolism and successful malpractice liability claims are the principle reasons for the dramatic decline in the use of the sitting position in neurosurgical practice. Although there have been several studies substantiating the relative safety compared with the prone or park bench positions, its use will continue to decline as neurosurgeons abandon its application and trainees in neurosurgery are not exposed to its relative merits. How can individual surgeons continue to use this position? Will individual, difficult surgical access cases be denied the obvious technical advantages of the sitting position? Limited use of the sitting position should remain in the neurosurgeon's armamentarium. However, several caveats must be emphasized. Assessment of the relative risk-benefit, based on the individual patient's physical status and surgical implications for the particular intracranial pathology, is of paramount importance. The patient should be informed of the specific risks of venous air embolism, quadriparesis and peripheral nerve palsies. Appropriate charting of patient information provided and special consent issues are essential. An anaesthetic input into the decision to use the sitting position is a sine qua non. The presence of a patient foramen ovale is an absolute contraindication. Preoperative contrast echocardiography should be used as a screening technique to detect the population at risk of paradoxical air embolism caused by the presence of a patent foramen ovale. The technique involves i.v. injection of saline agitated with air and a Valsalva manoeuvre is applied and released. Use of this position necessitates supplementary monitoring to promptly detect and treat venous air embolism. Doppler ultrasonography is the most sensitive of the generally available monitors to detect intracardiac air. The use of a central venous catheter is recommended, with the tip positioned close to the superior vena cava

  19. Experimental characterization of the transfer function for a Silver-dielectric superlens.

    PubMed

    Moore, Ciaran P; Blaikie, Richard J

    2012-03-12

    We describe a technique for experimentally determining the spatial-frequency modulation transfer function for near-field super-resolution imaging systems and present such a modulation transfer function for a 20|40|20 nm poly(vinyl alcohol)~(PVA)|Silver|PVA superlens exposed to 365 nm wavelength (i-line) radiation through a 50-nm thick tungsten mask. An extensive spectral characterization is achieved from only two exposures, with transmission coefficients determined for spatial frequencies as high as 13 µm-1, corresponding to λ / 4.75. The resulting transfer function is in good agreement with analytical models that incorporate the effects of mask-superlens interactions. PMID:22418523

  20. New technologies in neurosurgery: Effects on the conventional techniques and anaesthesiological considerations

    NASA Astrophysics Data System (ADS)

    Fasano, V. A.; Lombard, G. F.; Urciuoli, R.; Benech, F.; Ponzio, R. M.

    1985-09-01

    New technologies have been recently introduced into neurosurgery: laser sources, ultrasonic aspiration, intraoperative echotomography and intraoperative Doppler flowmeter. The aim of this work, showing the use of these instruments in different neurosurgical operations, is to discuss the effective improvements of the surgical techniques when comparing new and traditional technologies. The laser is able to concentrate high energies in restricted areas allowing a maximum selectivity. Having a superficial destructive effect with associated hemostasis, CO 2 and argon are suitable in dissection maneuvers. Nd:YAG produces a high thermal diffusion, consenting a deeper and extended tissue removal and a considerable reduction of intraoperative blood loss also in vascularized tumors. A promising field of application of the laser is the treatment of cerebral vascular malformations. In arterio-venous malformations the irradiation of the nidus with Nd:YAG produces a rapid obliteration of the pathologic vessels. This technique avoids the isolation of the feeding arteries and reduces the manipulation of the surrounding tissue. In small saccular aneurysms an argon laser is used to produce a shrinkage of the dilatation with consequent occlusion of the malformation. The ultrasonic aspirator is used in the tumoral surgery to obtain a more rapid demolition of the mass by fragmentation and suction. Intraoperative echotomography consents a sharp topographic localization of the lesion, particularly in deeper cerebral areas, providing data on the nature of solid tumors. The intraoperative Doppler flowmeter is useful for identification of the feeding arteries and the shunt of the small deep-seated arterio-venous malformations consenting a dynamic evaluation of the operation. General anaesthesia in neurosurgical procedures is favourably influenced by laser use. Conventional anaesthetic techniques, however, must be modified to avoid the harmful effect of the laser, depending on the movements

  1. Integration of patient specific modeling and advanced image processing techniques for image-guided neurosurgery

    NASA Astrophysics Data System (ADS)

    Archip, Neculai; Fedorov, Andriy; Lloyd, Bryn; Chrisochoides, Nikos; Golby, Alexandra; Black, Peter M.; Warfield, Simon K.

    2006-03-01

    A major challenge in neurosurgery oncology is to achieve maximal tumor removal while avoiding postoperative neurological deficits. Therefore, estimation of the brain deformation during the image guided tumor resection process is necessary. While anatomic MRI is highly sensitive for intracranial pathology, its specificity is limited. Different pathologies may have a very similar appearance on anatomic MRI. Moreover, since fMRI and diffusion tensor imaging are not currently available during the surgery, non-rigid registration of preoperative MR with intra-operative MR is necessary. This article presents a translational research effort that aims to integrate a number of state-of-the-art technologies for MRI-guided neurosurgery at the Brigham and Women's Hospital (BWH). Our ultimate goal is to routinely provide the neurosurgeons with accurate information about brain deformation during the surgery. The current system is tested during the weekly neurosurgeries in the open magnet at the BWH. The preoperative data is processed, prior to the surgery, while both rigid and non-rigid registration algorithms are run in the vicinity of the operating room. The system is tested on 9 image datasets from 3 neurosurgery cases. A method based on edge detection is used to quantitatively validate the results. 95% Hausdorff distance between points of the edges is used to estimate the accuracy of the registration. Overall, the minimum error is 1.4 mm, the mean error 2.23 mm, and the maximum error 3.1 mm. The mean ratio between brain deformation estimation and rigid alignment is 2.07. It demonstrates that our results can be 2.07 times more precise then the current technology. The major contribution of the presented work is the rigid and non-rigid alignment of the pre-operative fMRI with intra-operative 0.5T MRI achieved during the neurosurgery.

  2. A value-based, no-cost-to-patient health model in the developing world: Critical appraisal of a unique patient-centric neurosurgery unit

    PubMed Central

    Thakar, Sumit; Dadlani, Ravi; Sivaraju, Laxminadh; Aryan, Saritha; Mohan, Dilip; Sai Kiran, Narayanam Anantha; Rajarathnam, Ravikiran; Shyam, Maya; Sadanand, Venkatraman; Hegde, Alangar S.

    2015-01-01

    Background: It is well-accepted that the current healthcare scenario worldwide is due for a radical change, given that it is fraught with mounting costs and varying quality. Various modifications in health policies have been instituted toward this end. An alternative model, the low-cost, value-based health model, focuses on maximizing value for patients by moving away from a physician-centered, supply-driven system to a patient-centered system. Methods: The authors discuss the successful inception, functioning, sustainability, and replicability of a novel health model in neurosurgery built and sustained by inspired humanitarianism and that provides all treatment at no cost to the patients irrespective of their socioeconomic strata, color or creed. Results: The Sri Sathya Sai Institute of Higher Medical Sciences (SSSIHMS) at Whitefield, Bengaluru, India, a private charitable hospital established in 2001, functions on the ideals of providing free state-of-the-art healthcare to all in a compassionate and holistic manner. With modern equipment and respectable outcome benchmarks, its neurosurgery unit has operated on around 18,000 patients since its inception, and as such, has contributed INR 5310 million (USD 88.5 million) to society from an economic standpoint. Conclusions: The inception and sustainability of the SSSIHMS model are based on self-perpetuating philanthropy, a cost-conscious culture and the dissemination of human values. Replicated worldwide, at least in the developing nations, this unique healthcare model may well change the face of healthcare economics. PMID:26322241

  3. Reproducibility and Variability of the Cost Functions Reconstructed from Experimental Recordings in Multi-Finger Prehension

    PubMed Central

    Niu, Xun; Latash, Mark L.; Zatsiorsky, Vladimir M.

    2012-01-01

    The main goal of the study is to examine whether the cost (objective) functions reconstructed from experimental recordings in multi-finger prehension tasks are reproducible over time, i.e., whether the functions reflect stable preferences of the subjects and can be considered personal characteristics of motor coordination. Young, healthy participants grasped an instrumented handle with varied values of external torque, load and target grasping force and repeated the trials on three days: Day 1, Day 2, and Day 7. By following Analytical Inverse Optimization (ANIO) computation procedures, the cost functions for individual subjects were reconstructed from the experimental recordings (individual finger forces) for each day. The cost functions represented second-order polynomials of finger forces with non-zero linear terms. To check whether the obtained cost functions were reproducible over time a cross-validation was performed: a cost function obtained on Day i was applied to experimental data observed on Day j (i≠j). In spite of the observed day-to-day variability of the performance and the cost functions, the ANIO reconstructed cost functions were found to be reproducible over time: application of a cost function Ci to the data of Day j (i≠j) resulted in smaller deviations from the experimental observations than using other commonly used cost functions. Other findings are: (a) The 2nd order coefficients Ki of the cost function showed negative linear relations with finger force magnitudes. This fact may be interpreted as encouraging involvement of stronger fingers in tasks requiring higher total force magnitude production. (b) The finger forces were distributed on a 2-dimensional plane in the 4-dimensional finger force space, which has been confirmed for all subjects and all testing sessions. (c) The discovered principal components in the principal component analysis of the finger forces agreed well with the principle of superposition, i.e. the complex action of

  4. Experimental approaches for addressing fundamental biological questions in living, functioning cells with single molecule precision

    PubMed Central

    Lenn, Tchern; Leake, Mark C.

    2012-01-01

    In recent years, single molecule experimentation has allowed researchers to observe biological processes at the sensitivity level of single molecules in actual functioning, living cells, thereby allowing us to observe the molecular basis of the key mechanistic processes in question in a very direct way, rather than inferring these from ensemble average data gained from traditional molecular and biochemical techniques. In this short review, we demonstrate the impact that the application of single molecule bioscience experimentation has had on our understanding of various cellular systems and processes, and the potential that this approach has for the future to really address very challenging and fundamental questions in the life sciences. PMID:22773951

  5. Reconstruction of the unknown optimization cost functions from experimental recordings during static multi-finger prehension

    PubMed Central

    Niu, Xun; Terekhov, Alexander V.; Latash, Mark L.; Zatsiorsky, Vladimir M.

    2013-01-01

    The goal of the research is to reconstruct the unknown cost (objective) function(s) presumably used by the neural controller for sharing the total force among individual fingers in multi-finger prehension. The cost function was determined from experimental data by applying the recently developed Analytical Inverse Optimization (ANIO) method (Terekhov et al 2010). The core of the ANIO method is the Theorem of Uniqueness that specifies conditions for unique (with some restrictions) estimation of the objective functions. In the experiment, subjects (n=8) grasped an instrumented handle and maintained it at rest in the air with various external torques, loads, and target grasping forces applied to the object. The experimental data recorded from 80 trials showed a tendency to lie on a 2-dimensional hyperplane in the 4-dimensional finger-force space. Because the constraints in each trial were different, such a propensity is a manifestation of a neural mechanism (not the task mechanics). In agreement with the Lagrange principle for the inverse optimization, the plane of experimental observations was close to the plane resulting from the direct optimization. The latter plane was determined using the ANIO method. The unknown cost function was reconstructed successfully for each performer, as well as for the group data. The cost functions were found to be quadratic with non-zero linear terms. The cost functions obtained with the ANIO method yielded more accurate results than other optimization methods. The ANIO method has an evident potential for addressing the problem of optimization in motor control. PMID:22104742

  6. Recent developments in optimal experimental designs for functional magnetic resonance imaging

    PubMed Central

    Kao, Ming-Hung; Temkit, M'hamed; Wong, Weng Kee

    2014-01-01

    Functional magnetic resonance imaging (fMRI) is one of the leading brain mapping technologies for studying brain activity in response to mental stimuli. For neuroimaging studies utilizing this pioneering technology, there is a great demand of high-quality experimental designs that help to collect informative data to make precise and valid inference about brain functions. This paper provides a survey on recent developments in experimental designs for fMRI studies. We briefly introduce some analytical and computational tools for obtaining good designs based on a specified design selection criterion. Research results about some commonly considered designs such as blocked designs, and m-sequences are also discussed. Moreover, we present a recently proposed new type of fMRI designs that can be constructed using a certain type of Hadamard matrices. Under certain assumptions, these designs can be shown to be statistically optimal. Some future research directions in design of fMRI experiments are also discussed. PMID:25071884

  7. Experimental triplet and quadruplet fluctuation densities and spatial distribution function integrals for liquid mixtures

    SciTech Connect

    Ploetz, Elizabeth A.; Smith, Paul E.

    2015-03-07

    Kirkwood-Buff or Fluctuation Solution Theory can be used to provide experimental pair fluctuations, and/or integrals over the pair distribution functions, from experimental thermodynamic data on liquid mixtures. Here, this type of approach is used to provide triplet and quadruplet fluctuations, and the corresponding integrals over the triplet and quadruplet distribution functions, in a purely thermodynamic manner that avoids the use of structure factors. The approach is then applied to binary mixtures of water + methanol and benzene + methanol over the full composition range under ambient conditions. The observed correlations between the different species vary significantly with composition. The magnitude of the fluctuations and integrals appears to increase as the number of the most polar molecule involved in the fluctuation or integral also increases. A simple physical picture of the fluctuations is provided to help rationalize some of these variations.

  8. Validation of MCDS by comparison of predicted with experimental velocity distribution functions in rarefied normal shocks

    NASA Technical Reports Server (NTRS)

    Pham-Van-diep, Gerald C.; Erwin, Daniel A.

    1989-01-01

    Velocity distribution functions in normal shock waves in argon and helium are calculated using Monte Carlo direct simulation. These are compared with experimental results for argon at M = 7.18 and for helium at M = 1.59 and 20. For both argon and helium, the variable-hard-sphere (VHS) model is used for the elastic scattering cross section, with the velocity dependence derived from a viscosity-temperature power-law relationship in the way normally used by Bird (1976).

  9. Electrocatalysis of borohydride oxidation: a review of density functional theory approach combined with experimental validation

    NASA Astrophysics Data System (ADS)

    Sison Escaño, Mary Clare; Lacdao Arevalo, Ryan; Gyenge, Elod; Kasai, Hideaki

    2014-09-01

    The electrocatalysis of borohydride oxidation is a complex, up-to-eight-electron transfer process, which is essential for development of efficient direct borohydride fuel cells. Here we review the progress achieved by density functional theory (DFT) calculations in explaining the adsorption of BH4- on various catalyst surfaces, with implications for electrocatalyst screening and selection. Wherever possible, we correlate the theoretical predictions with experimental findings, in order to validate the proposed models and to identify potential directions for further advancements.

  10. Localization and socialization: Experimental insights into the functional architecture of IP3 receptors

    NASA Astrophysics Data System (ADS)

    Diambra, Luis; Marchant, Jonathan S.

    2009-09-01

    Inositol 1,4,5-trisphosphate (IP3)-evoked Ca2+ signals display great spatiotemporal malleability. This malleability depends on diversity in both the cellular organization and in situ functionality of IP3 receptors (IP3Rs) that regulate Ca2+ release from the endoplasmic reticulum (ER). Recent experimental data imply that these considerations are not independent, such that—as with other ion channels—the local organization of IP3Rs impacts their functionality, and reciprocally IP3R activity impacts their organization within native ER membranes. Here, we (i) review experimental data that lead to our understanding of the "functional architecture" of IP3Rs within the ER, (ii) propose an updated terminology to span the organizational hierarchy of IP3Rs observed in intact cells, and (iii) speculate on the physiological significance of IP3R socialization in Ca2+ dynamics, and consequently the emerging need for modeling studies to move beyond gridded, planar, and static simulations of IP3R clustering even over short experimental timescales.

  11. A Comparison of Experimental Functional Analysis and the Questions about Behavioral Function (QABF) in the Assessment of Challenging Behavior of Individuals with Autism

    ERIC Educational Resources Information Center

    Healy, Olive; Brett, Denise; Leader, Geraldine

    2013-01-01

    We compared two functional behavioral assessment methods: the Questions About Behavioral Function (QABF; a standardized test) and experimental functional analysis (EFA) to identify behavioral functions of aggressive/destructive behavior, self-injurious behavior and stereotypy in 32 people diagnosed with autism. Both assessments found that self…

  12. Downregulation of FoxC2 Increased Susceptibility to Experimental Colitis: Influence of Lymphatic Drainage Function?

    PubMed Central

    Becker, Felix; Potepalov, Sergey; Shehzahdi, Romana; Bernas, Michael; Witte, Marlys; Abreo, Fleurette; Traylor, James; Orr, Wayne A.; Tsunoda, Ikuo

    2015-01-01

    Background: Although inflammation-induced expansion of the intestinal lymphatic vasculature (lymphangiogenesis) is known to be a crucial event in limiting inflammatory processes, through clearance of interstitial fluid and immune cells, considerably less is known about the impact of an impaired lymphatic clearance function (as seen in inflammatory bowel diseases) on this cascade. We aimed to investigate whether the impaired intestinal lymphatic drainage function observed in FoxC2(+/−) mice would influence the course of disease in a model of experimental colitis. Methods: Acute dextran sodium sulfate colitis was induced in wild-type and haploinsufficient FoxC2(+/−) mice, and survival, disease activity, colonic histopathological injury, neutrophil, T-cell, and macrophage infiltration were evaluated. Functional and structural changes in the intestinal lymphatic vessel network were analyzed, including submucosal edema, vessel morphology, and lymphatic vessel density. Results: We found that FoxC2 downregulation in FoxC2(+/−) mice significantly increased the severity and susceptibility to experimental colitis, as displayed by lower survival rates, increased disease activity, greater histopathological injury, and elevated colonic neutrophil, T-cell, and macrophage infiltration. These findings were accompanied by structural (dilated torturous lymphatic vessels) and functional (greater submucosal edema, higher immune cell burden) changes in the intestinal lymphatic vasculature. Conclusions: These results indicate that sufficient lymphatic clearance plays a crucial role in limiting the initiation and perpetuation of experimental colitis and those disturbances in the integrity of the intestinal lymphatic vessel network could intensify intestinal inflammation. Future therapies might be able to exploit these processes to restore and maintain adequate lymphatic clearance function in inflammatory bowel disease. PMID:25822012

  13. An abrupt reduction in end-tidal carbon-dioxide during neurosurgery is not always due to venous air embolism: a capnograph artefact.

    PubMed

    Vinay, Byrappa; Sriganesh, Kamath; Gopala Krishna, Kadarapura Nanjundaiah

    2014-04-01

    Venous air embolism (VAE) is a well recognized complication during neurosurgery. Pre-cordial doppler and trans-esophageal echocardiography are sensitive monitors for the detection of VAE. A sudden, abrupt reduction in the end-tidal carbondioxide (ETCO2) pressure with associated hypotension during neurosurgery might suggest VAE, when more sensitive monitors are not available. We describe an unusual cause for sudden reduction in ETCO2 during neurosurgery and discuss the mechanism for such presentation. PMID:23996497

  14. Alfvénic oscillations of the electron distribution function: Linear theory and experimental measurements

    SciTech Connect

    Schroeder, J. W. R. Skiff, F.; Howes, G. G.; Kletzing, C. A.; Carter, T. A.; Dorfman, S.

    2015-12-10

    Wave propagation can be an accurate method for determining material properties. High frequency whistler mode waves (0.7 < ω/|Ω{sub ce}| < 1) in an overdense plasma (ω{sub pe} > |Ω{sub ce}|) are damped primarily by Doppler-shifted electron cyclotron resonance. A kinetic description of whistler mode propagation parallel to the background magnetic field shows that damping is proportional to the parallel electron distribution function. This property enables an experimental determination of the parallel electron distribution function using a measurement of whistler mode wave absorption. The whistler mode wave absorption diagnostic uses this technique on UCLA’s Large Plasma Device (LaPD) to measure the distribution of high energy electrons (5 − 10v{sub te}) with 0.1% precision. The accuracy is limited by systematic effects that need to be considered carefully. Ongoing research uses this diagnostic to investigate the effect of inertial Alfvén waves on the electron distribution function. Results presented here verify experimentally the linear effects of inertial Alfvén waves on the reduced electron distribution function, a necessary step before nonlinear physics can be tested. Ongoing experiments with the whistler mode wave absorption diagnostic are making progress toward the first direct detection of electrons nonlinearly accelerated by inertial Alfvén waves, a process believed to play an important role in auroral generation.

  15. Numerical and experimental studies of enhanced electron emission from functionalized carbon nanotube emitters

    NASA Astrophysics Data System (ADS)

    Jin, Feng; Little, Scott; Alzubi, Feras

    2007-03-01

    Vertically aligned carbon nanotubes (CNTs) were grown using plasma enhanced chemical vapor deposition (PECVD) method. The CNTs were further functionalized by coating their surface with a thin layer of low work function oxide emissive materials. The electron emission capability of the coated CNT emitters was greatly improved with the low work function emissive layer, particularly at high temperature. Thermionic emission current three orders magnitude higher was observed. The emission properties of the oxide coated CNTs were measured and characterized over a wide temperature and field ranges. It was found that neither the Fowler-Nordheim theory for field emission nor the Richardson theory for thermionic emission were adequate to describe the electron emission characteristics of these emitters in certain range of temperature and field. However, by adopting a general electron emission formulism developed by Murphy and Good, we were able to simulate the electron emission from the coated CNTs over the whole temperature and field range and fit the experimental data.

  16. Preliminary Results on the Experimental Investigation of the Structure Functions of Bound Nucleons

    SciTech Connect

    Bodek, Arie

    2015-09-01

    We present preliminary results on an experimental study of the nuclear modification of the longitudinal (σL) and transverse (σT) structure functions of nucleons bound in nuclear targets. The origin of these modifications (commonly referred as as the EMC effect) is not fully understood. Our measurements of R= σLT for nuclei (RA) and for deuterium (RD) indicate that nuclear modifications of the structure functions of bound nucleons are different for the longitudinal and transverse structure functions, and that contrary to expectation from several theoretical models, RA < RD.

  17. The Richard C. Schneider Lecture. New dimensions of neurosurgery in the realm of high technology: possibilities, practicalities, realities.

    PubMed

    Apuzzo, M L

    1996-04-01

    Fueled by a buoyant economy, popular attitudes and demands, and parallel progress in transferable technical and biological areas, neurosurgery has enjoyed a remarkable quarter of a century of progress. Developmental trends in the discipline have included the following: 1) a refinement of preoperative definition of the structural substrate, 2) miniaturization of operative corridors, 3) reduction of operative trauma, 4) increased effectiveness at the target site, and 5) incorporation of improved technical adjuvants and physical operative tools into treatment protocols. In particular, the computer has become a formidable ally in diagnostic and surgical events. Trends in technical development indicate that we are entering an exciting era of advanced surgery of the human cerebrum, which is heralded by the following: 1) current developments in areas of imaging, sensors, and visualization; 2) new devices for localization and navigation; 3) new capabilities for action at the target point; and 4) innovative concepts related to advanced operative venues. Imaging has provided structurally based surgical maps, which now are being given the new dimension of function in complex and integrated formats for preoperative planning and intraoperative tactical direction. Cerebral localization and navigation based on these advances promise to provide further refinement to the field of stereotactic neurosurgery, as linked systems are superseded by more flexible nonlinked methodologies in functionally defined volume-oriented navigational databases. Target point action now includes not only ablative capabilities through micro-operative methods and the use of stereotactically directed high-energy forms but also the emergence of restorative capabilities through applications of principles of genetic engineering in the areas of molecular and cellular neurosurgery. Complex, dedicated, and self-contained operative venues will be required to optimize the emergence and development of these

  18. 100 Years of British military neurosurgery: on the shoulders of giants.

    PubMed

    Roberts, S A G

    2015-01-01

    Death from head injuries has been a feature of conflicts throughout the world for centuries. The burden of mortality has been variously affected by the evolution in weaponry from war-hammers to explosive ordnance, the influence of armour on survivability and the changing likelihood of infection as a complicating factor. Surgery evolved from haphazard trephination to valiant, yet disjointed, neurosurgery by a variety of great historical surgeons until the Crimean War of 1853-1856. However, it was events initiated by the Great War of 1914-1918 that not only marked the development of modern neurosurgical techniques, but our approach to military surgery as a whole. Here the author describes how 100 years of conflict and the input and intertwining relationships between the 20th century's great neurosurgeons established neurosurgery in the United Kingdom and beyond. PMID:26292388

  19. Propionibacterium Acnes Brain Abscess in an Immunocompetent Man in the Absence of Prior Neurosurgery.

    PubMed

    Odunukan, Olufunso W; Masannat, Fares; Baka, J Jeff

    2016-02-01

    Propionibacterium acnes is a rare, but established, cause of intracranial abscesses. We describe a case of P. acnes brain abscess in an immunocompetent man without prior neurosurgery. A 49-year old man with mild psoriasis presented with a two-week history of gait changes, generalized weakness and a two-day history of headaches, aphasia and confusion. Imaging revealed a left thalamic mass and surgical biopsy suggested a pyogenic abscess. Cultures of biopsy samples of the abscess grew P. acnes alone. MRI and serial neurological exam showed marked clinical improvement with intravenous antibiotics. The significant reduction in the abscess was sustained on MRI obtained at six weeks after completion of antibiotic therapy. In conclusion, P. acnes must be considered as a differential diagnosis in individuals presenting with features suggestive of a brain abscess even in the absence of immunosuppression or previous neurosurgery. PMID:26999913

  20. Stereotactic neurosurgery in the United Kingdom: the hundred years from Horsley to Hariz.

    PubMed

    Pereira, Erlick A C; Green, Alexander L; Nandi, Dipankar; Aziz, Tipu Z

    2008-09-01

    The history of stereotactic neurosurgery in the United Kingdom of Great Britain and Northern Ireland is reviewed. Horsley and Clarke's primate stereotaxy at the turn of the 20th century and events surrounding it are described, including Mussen's development of a human version of the apparatus. Stereotactic surgery after the Second World War is reviewed, with an emphasis on the pioneering work of Gillingham, Hitchcock, Knight, and Watkins and the contributions from Bennett, Gleave, Hughes, Johnson, McKissock, McCaul, and Dutton after the influences of Dott, Cairns, and Jefferson. Forster's introduction of gamma knife radiosurgery is summarized, as is the application of computed tomography by Hounsfield and Ambrose. Contemporary contributions to the present day from Bartlett, Richardson, Miles, Thomas, Gill, Aziz, Hariz, and others are summarized. The current status of British stereotactic neurosurgery is discussed. PMID:18812971

  1. Impact of 20th Century Wars on the Development of Neurosurgery.

    PubMed

    Dowdy, Justin; Pait, T Glenn

    2016-01-01

    The treatment of neurosurgical casualties suffered during the wars of the 20th century had a significant impact on the formation and early growth of neurosurgery as a specialty. This chapter explores how the evolution of military tactics and weaponry along with the circumstances surrounding the wars themselves profoundly influenced the field. From the crystallization of intracranial projectile wound management and the formal recognition of the specialty itself arising from World War I experiences to the radical progress made in the outcomes of spinal-cord-injured soldiers in World War II or the fact that the neurosurgical training courses commissioned for these wars proved to be the precursors to modern neurosurgical training programs, the impact of the 20th century wars on the development of the field of neurosurgery is considerable. PMID:27035828

  2. Diabetes insipidus following neurosurgery at a university hospital in Western Saudi Arabia

    PubMed Central

    Qari, Faiza A.; AbuDaood, Elaff A.; Nasser, Tariq A.

    2016-01-01

    Objectives: To review the incidence, spectrum of clinical manifestation, course, risk factors, as well as treatment of diabetes insipidus (DI) following neurosurgery of the pituitary gland. Methods: The files of 24 patients that underwent neurosurgery for sellar lesions, or tumor near the hypothalamus or pituitary gland at the Department of Neurosurgery, King Abdulaziz University Hospital, Jeddah, Kingdom of Saudi Arabia were retrospectively reviewed between January 2011 to December 2014. A total of 24 patients were studied, and were divided into 2 groups namely; DI and non-DI. Patient characteristics were studied using descriptive statistics. The differences in proportion between the 2 groups were found out using Z-test for proportion in 2 populations. The mean differences in the hormonal abnormalities for the 2 groups were assessed using independent t-test. All statistics are considered statistically significant when p<0.05. Results: During hospitalization, 13 (54.2%) out of 24 patient that underwent neurosurgery had manifestations of DI, which was transient in 5 (38.8%) and permanent in 8 (61.2%). The DI subgroup contained higher prevalence of prolactinoma, craniopharyngioma, pre-operative panhypopituitarism, and macroadenoma in MRI imaging and transphenoidal surgery. Furthermore, urine osmolality was significantly lower in the DI group post-operatively with a significant p=0.023. It was recognized that the permanent DI documented more significant numbers than other studies. Conclusion: In our study group, it was recognized that permanent DI meant that our patients needed desmopressin for more than 3 months, which documented a more significant number than other studies. PMID:26837398

  3. The present and future of quality measures and public reporting in neurosurgery.

    PubMed

    Bekelis, Kimon; McGirt, Matthew J; Parker, Scott L; Holland, Christopher M; Davies, Jason; Devin, Clinton J; Atkins, Tyler; Knightly, Jack; Groman, Rachel; Zyung, Irene; Asher, Anthony L

    2015-12-01

    Quality measurement and public reporting are intended to facilitate targeted outcome improvement, practice-based learning, shared decision making, and effective resource utilization. However, regulatory implementation has created a complex network of reporting requirements for physicians and medical practices. These include Medicare's Physician Quality Reporting System, Electronic Health Records Meaningful Use, and Value-Based Payment Modifier programs. The common denominator of all these initiatives is that to avoid penalties, physicians must meet "generic" quality standards that, in the case of neurosurgery and many other specialties, are not pertinent to everyday clinical practice and hold specialists accountable for care decisions outside of their direct control. The Centers for Medicare and Medicaid Services has recently authorized alternative quality reporting mechanisms for the Physician Quality Reporting System, which allow registries to become subspecialty-reporting mechanisms under the Qualified Clinical Data Registry (QCDR) program. These programs further give subspecialties latitude to develop measures of health care quality that are relevant to the care provided. As such, these programs amplify the power of clinical registries by allowing more accurate assessment of practice patterns, patient experiences, and overall health care value. Neurosurgery has been at the forefront of these developments, leveraging the experience of the National Neurosurgery Quality and Outcomes Database to create one of the first specialty-specific QCDRs. Recent legislative reform has continued to change this landscape and has fueled optimism that registries (including QCDRs) and other specialty-driven quality measures will be a prominent feature of federal and private sector quality improvement initiatives. These physician- and patient-driven methods will allow neurosurgery to underscore the value of interventions, contribute to the development of sustainable health care

  4. Virtual reality training in neurosurgery: Review of current status and future applications

    PubMed Central

    Alaraj, Ali; Lemole, Michael G.; Finkle, Joshua H.; Yudkowsky, Rachel; Wallace, Adam; Luciano, Cristian; Banerjee, P. Pat; Rizzi, Silvio H.; Charbel, Fady T.

    2011-01-01

    Background: Over years, surgical training is changing and years of tradition are being challenged by legal and ethical concerns for patient safety, work hour restrictions, and the cost of operating room time. Surgical simulation and skill training offer an opportunity to teach and practice advanced techniques before attempting them on patients. Simulation training can be as straightforward as using real instruments and video equipment to manipulate simulated “tissue” in a box trainer. More advanced virtual reality (VR) simulators are now available and ready for widespread use. Early systems have demonstrated their effectiveness and discriminative ability. Newer systems enable the development of comprehensive curricula and full procedural simulations. Methods: A PubMed review of the literature was performed for the MESH words “Virtual reality, “Augmented Reality”, “Simulation”, “Training”, and “Neurosurgery”. Relevant articles were retrieved and reviewed. A review of the literature was performed for the history, current status of VR simulation in neurosurgery. Results: Surgical organizations are calling for methods to ensure the maintenance of skills, advance surgical training, and credential surgeons as technically competent. The number of published literature discussing the application of VR simulation in neurosurgery training has evolved over the last decade from data visualization, including stereoscopic evaluation to more complex augmented reality models. With the revolution of computational analysis abilities, fully immersive VR models are currently available in neurosurgery training. Ventriculostomy catheters insertion, endoscopic and endovascular simulations are used in neurosurgical residency training centers across the world. Recent studies have shown the coloration of proficiency with those simulators and levels of experience in the real world. Conclusion: Fully immersive technology is starting to be applied to the practice of

  5. Experimental

    NASA Astrophysics Data System (ADS)

    Gütlich, Philipp; Bill, Eckhard; Trautwein, Alfred X.

    In this chapter, we present the principles of conventional Mössbauer spectrometers with radioactive isotopes as the light source; Mössbauer experiments with synchrotron radiation are discussed in Chap. 9 including technical principles. Since complete spectrometers, suitable for virtually all the common isotopes, have been commercially available for many years, we refrain from presenting technical details like electronic circuits. We are concerned here with the functional components of a spectrometer, their interaction and synchronization, the different operation modes and proper tuning of the instrument. We discuss the properties of radioactive γ-sources to understand the requirements of an efficient γ-counting system, and finally we deal with sample preparation and the optimization of Mössbauer absorbers. For further reading on spectrometers and their technical details, we refer to the review articles [1-3].

  6. Atrial natriuretic factor: is it responsible for hyponatremia and natriuresis in neurosurgery?

    PubMed Central

    Gasparotto, Ana Paula Devite Cardoso; Falcão, Antonio Luis Eiras; Kosour, Carolina; Araújo, Sebastião; Cintra, Eliane Araújo; de Oliveira, Rosmari Aparecida Rosa Almeida; Martins, Luiz Claudio; Dragosavac, Desanka

    2016-01-01

    Objective To evaluate the presence of hyponatremia and natriuresis and their association with atrial natriuretic factor in neurosurgery patients. Methods The study included 30 patients who had been submitted to intracranial tumor resection and cerebral aneurism clipping. Both plasma and urinary sodium and plasma atrial natriuretic factor were measured during the preoperative and postoperative time periods. Results Hyponatremia was present in 63.33% of the patients, particularly on the first postoperative day. Natriuresis was present in 93.33% of the patients, particularly on the second postoperative day. Plasma atrial natriuretic factor was increased in 92.60% of the patients in at least one of the postoperative days; however, there was no statistically significant association between the atrial natriuretic factor and plasma sodium and between the atrial natriuretic factor and urinary sodium. Conclusion Hyponatremia and natriuresis were present in most patients after neurosurgery; however, the atrial natriuretic factor cannot be considered to be directly responsible for these alterations in neurosurgery patients. Other natriuretic factors are likely to be involved. PMID:27410411

  7. Neurosurgery at All India Institute of Medical Sciences, a center of excellence: A success story.

    PubMed

    Singh, Manmohan; Sawarkar, Dattaraj; Sharma, Bhawani S

    2015-01-01

    The department of neurosurgery at All India Institute of Medical Sciences (AIIMS) started its humble beginning in 1965. With the untiring and selfless hard work of Prof. P N Tandon and Prof. A K Banerji, the department progressed over time to become a center of excellence in the subcontinent. To establish a neurosciences center at AIIMS was an uphill task, which was accomplished with great efforts. The department has established itself as one of the highest centers of learning in the country with its vast infrastructure and diversity in all fields of neurosurgery. AIIMS, New Delhi was established by an act of the parliament in 1956. It was started with a grant from the Government of New Zealand under the "Colombo Plan." It was the vision of Rajkumari Amrita Kaur, the first Health Minister of India, that led to the establishment of a medical institute of international repute in India. AIIMS, New Delhi is an autonomous institute and is governed by the AIIMS Act, 1956. The department of neurosurgery at AIIMS was started in March 1965 with Prof. P.N. Tandon as the Head of the Department. Prof. A.K. Banerji joined him a few months later. The Department celebrated its golden jubilee in the year 2015, and has tremendously grown in stature from its humble beginnings to being a center of excellence with world-wide recognition. PMID:26238896

  8. The Department of Neurosurgery at Seoul National University: past, present, and future.

    PubMed

    Kim, D G; Kim, H J

    2001-04-01

    The Department of Neurosurgery at Seoul National University College of Medicine is one of the oldest neurosurgical departments in Korea, and it is a center of academic leadership in neurosurgery. In September 1957, the department was established by Bo Sung Sim, and it has produced many leaders of neurosurgery in Korea. Chairmen Bo Sung Sim, Kil Soo Choi, Dae Hee Han, and Byung-Kyu Cho each brought special skills and talents to the development of the department. The current and fifth chair, Hyun Jib Kim, assumed the chairmanship in July 2000. The department comprises 11 full-time faculty members, 5 fellows, and 14 residents. More than 1,700 neurosurgical procedures are performed annually in four operating theaters. A gamma knife was installed in 1997, and approximately 200 gamma knife procedures are performed each year. In addition to clinical activities, research and education for graduate and postgraduate students are also particular strengths of the department. This article traces the clinical, academic, and scientific development of the department, its present activities, and its future direction. PMID:11322453

  9. The National Neurosurgery Quality and Outcomes Database Qualified Clinical Data Registry: 2015 measure specifications and rationale.

    PubMed

    Parker, Scott L; McGirt, Matthew J; Bekelis, Kimon; Holland, Christopher M; Davies, Jason; Devin, Clinton J; Atkins, Tyler; Knightly, Jack; Groman, Rachel; Zyung, Irene; Asher, Anthony L

    2015-12-01

    Meaningful quality measurement and public reporting have the potential to facilitate targeted outcome improvement, practice-based learning, shared decision making, and effective resource utilization. Recent developments in national quality reporting programs, such as the Centers for Medicare & Medicaid Services Qualified Clinical Data Registry (QCDR) reporting option, have enhanced the ability of specialty groups to develop relevant quality measures of the care they deliver. QCDRs will complete the collection and submission of Physician Quality Reporting System (PQRS) quality measures data on behalf of individual eligible professionals. The National Neurosurgery Quality and Outcomes Database (N(2)QOD) offers 21 non-PQRS measures, initially focused on spine procedures, which are the first specialty-specific measures for neurosurgery. Securing QCDR status for N(2)QOD is a tremendously important accomplishment for our specialty. This program will ensure that data collected through our registries and used for PQRS is meaningful for neurosurgeons, related spine care practitioners, their patients, and other stakeholders. The 2015 N(2)QOD QCDR is further evidence of neurosurgery's commitment to substantively advancing the health care quality paradigm. The following manuscript outlines the measures now approved for use in the 2015 N(2)QOD QCDR. Measure specifications (measure type and descriptions, related measures, if any, as well as relevant National Quality Strategy domain[s]) along with rationale are provided for each measure. PMID:26621418

  10. Laser speckle contrast imaging of cerebral blood flow in humans during neurosurgery: a pilot clinical study

    NASA Astrophysics Data System (ADS)

    Parthasarathy, Ashwin B.; Weber, Erica L.; Richards, Lisa M.; Fox, Douglas J.; Dunn, Andrew K.

    2010-11-01

    Monitoring cerebral blood flow (CBF) during neurosurgery can provide important physiological information for a variety of surgical procedures. CBF measurements are important for assessing whether blood flow has returned to presurgical baseline levels and for assessing postsurgical tissue viability. Existing techniques for intraoperative monitoring of CBF based on magnetic resonance imaging are expensive and often impractical, while techniques such as indocyanine green angiography cannot produce quantitative measures of blood flow. Laser speckle contrast imaging (LSCI) is an optical technique that has been widely used to quantitatively image relative CBF in animal models in vivo. In a pilot clinical study, we adapted an existing neurosurgical operating microscope to obtain LSCI images in humans in real time during neurosurgery under baseline conditions and after bipolar cautery. Simultaneously recorded ECG waveforms from the patient were used to develop a filter that helped reduce measurement variabilities due to motion artifacts. Results from this study demonstrate the feasibility of using LSCI to obtain blood flow images during neurosurgeries and its capability to produce full field CBF image maps with excellent spatial resolution in real-time with minimal disruption to the surgical procedure.

  11. Structure of amorphous Ag/Ge/S alloys: experimentally constrained density functional study.

    PubMed

    Akola, J; Beuneu, B; Jones, R O; Jóvári, P; Kaban, I; Kolář, J; Voleská, I; Wágner, T

    2015-12-01

    Density functional/molecular dynamics simulations have been performed to determine structural and other properties of amorphous Ag/Ge/S and Ge/S alloys. In the former, the calculations have been combined with experimental data (x-ray and neutron diffraction, extended x-ray absorption fine structure). Ag/Ge/As alloys have high ionic conductivity and are among the most promising candidates for future memristor technology. We find excellent agreement between the experimental results and large-scale (500 atoms) simulations in Ag/Ge/S, and we compare and contrast the structures of Ge/S and Ag/Ge/S. The calculated electronic structures, vibrational densities of states, ionic mobilities, and cavity distributions of the amorphous materials are discussed and compared with data on crystalline phases where available. The high mobility of Ag in solid state electrolyte applications is related to the presence of cavities and can occur via jumps to a neighbouring vacant site. PMID:26569035

  12. Structure of amorphous Ag/Ge/S alloys: experimentally constrained density functional study

    NASA Astrophysics Data System (ADS)

    Akola, J.; Beuneu, B.; Jones, R. O.; Jóvári, P.; Kaban, I.; Kolář, J.; Voleská, I.; Wágner, T.

    2015-12-01

    Density functional/molecular dynamics simulations have been performed to determine structural and other properties of amorphous Ag/Ge/S and Ge/S alloys. In the former, the calculations have been combined with experimental data (x-ray and neutron diffraction, extended x-ray absorption fine structure). Ag/Ge/As alloys have high ionic conductivity and are among the most promising candidates for future memristor technology. We find excellent agreement between the experimental results and large-scale (500 atoms) simulations in Ag/Ge/S, and we compare and contrast the structures of Ge/S and Ag/Ge/S. The calculated electronic structures, vibrational densities of states, ionic mobilities, and cavity distributions of the amorphous materials are discussed and compared with data on crystalline phases where available. The high mobility of Ag in solid state electrolyte applications is related to the presence of cavities and can occur via jumps to a neighbouring vacant site.

  13. DIANA-miRPath v3.0: deciphering microRNA function with experimental support.

    PubMed

    Vlachos, Ioannis S; Zagganas, Konstantinos; Paraskevopoulou, Maria D; Georgakilas, Georgios; Karagkouni, Dimitra; Vergoulis, Thanasis; Dalamagas, Theodore; Hatzigeorgiou, Artemis G

    2015-07-01

    The functional characterization of miRNAs is still an open challenge. Here, we present DIANA-miRPath v3.0 (http://www.microrna.gr/miRPathv3) an online software suite dedicated to the assessment of miRNA regulatory roles and the identification of controlled pathways. The new miRPath web server renders possible the functional annotation of one or more miRNAs using standard (hypergeometric distributions), unbiased empirical distributions and/or meta-analysis statistics. DIANA-miRPath v3.0 database and functionality have been significantly extended to support all analyses for KEGG molecular pathways, as well as multiple slices of Gene Ontology (GO) in seven species (Homo sapiens, Mus musculus, Rattus norvegicus, Drosophila melanogaster, Caenorhabditis elegans, Gallus gallus and Danio rerio). Importantly, more than 600 000 experimentally supported miRNA targets from DIANA-TarBase v7.0 have been incorporated into the new schema. Users of DIANA-miRPath v3.0 can harness this wealth of information and substitute or combine the available in silico predicted targets from DIANA-microT-CDS and/or TargetScan v6.2 with high quality experimentally supported interactions. A unique feature of DIANA-miRPath v3.0 is its redesigned Reverse Search module, which enables users to identify and visualize miRNAs significantly controlling selected pathways or belonging to specific GO categories based on in silico or experimental data. DIANA-miRPath v3.0 is freely available to all users without any login requirement. PMID:25977294

  14. Experimental electron energy distribution function investigation at initial stage of electron cyclotron resonance discharge

    SciTech Connect

    Golubev, S. V.; Izotov, I. V.; Mansfeld, D. A.; Semenov, V. E.

    2012-02-15

    Experimental investigation is undertaken to study formation of electron energy distribution function (EEDF) at the initial stage of electron cyclotron resonance (ECR) discharge inside magnetic mirror trap. In experiment, where discharge was initiated by high power radiation of gyrotron operated in the mm-wavelength range, electrons were revealed to leave the trap having EEDF be quite different from Maxwellian one. Specifically, the EEDF was found to decrease slowly with energy up to 400-500 keV and drops abruptly further. The possible physical mechanisms are discussed to explain losses of high energy electrons from the trap and a limitation of their energy.

  15. Experimental electron energy distribution function investigation at initial stage of electron cyclotron resonance discharge.

    PubMed

    Golubev, S V; Izotov, I V; Mansfeld, D A; Semenov, V E

    2012-02-01

    Experimental investigation is undertaken to study formation of electron energy distribution function (EEDF) at the initial stage of electron cyclotron resonance (ECR) discharge inside magnetic mirror trap. In experiment, where discharge was initiated by high power radiation of gyrotron operated in the mm-wavelength range, electrons were revealed to leave the trap having EEDF be quite different from Maxwellian one. Specifically, the EEDF was found to decrease slowly with energy up to 400-500 keV and drops abruptly further. The possible physical mechanisms are discussed to explain losses of high energy electrons from the trap and a limitation of their energy. PMID:22380303

  16. Comparison between skin-mounted fiducials and bone-implanted fiducials for image-guided neurosurgery

    NASA Astrophysics Data System (ADS)

    Rost, Jennifer; Harris, Steven S.; Stefansic, James D.; Sillay, Karl; Galloway, Robert L., Jr.

    2004-05-01

    Point-based registration for image-guided neurosurgery has become the industry standard. While the use of intrinsic points is appealing because of its retrospective nature, affixing extrinsic objects to the head prior to scanning has been demonstrated to provide much more accurate registrations. Points of reference between image space and physical space are called fiducials. The extrinsic objects which generate those points are fiducial markers. The markers can be broken down into two classifications: skin-mounted and bone-implanted. Each has distinct advantages and disadvantages. Skin-mounted fiducials require simply sticking them on the patient in locations suggested by the manufacturer, however, they can move with tractions placed on the skin, fall off and perhaps the most dangerous problem, they can be replaced by the patient. Bone implanted markers being rigidly affixed to the skull do not present such problems. However, a minor surgical intervention (analogous to dental work) must be performed to implant the markers prior to surgery. Therefore marker type and use has become a decision point for image-guided surgery. We have performed a series of experiments in an attempt to better quantify aspects of the two types of markers so that better informed decisions can be made. We have created a phantom composed of a full-size plastic skull [Wards Scientific Supply] with a 500 ml bag of saline placed in the brain cavity. The skull was then sealed. A skin mimicking material, DragonSkinTM [SmoothOn Company] was painted onto the surface and allowed to dry. Skin mounted fiducials [Medtronic-SNT] and bone-implanted markers [Z-Kat]were placed on the phantom. In addition, three additional bone-implanted markers were placed (two on the base of the skull and one in the eye socket for use as targets). The markers were imaged in CT and 4 MRI sequences (T1-weighted, T2 weighted, SPGR, and a functional series.) The markers were also located in physical space using an Optotrak

  17. Electronic and optical response of functionalized Ru(II) complexes: joint theoretical and experimental study

    SciTech Connect

    Kilina, Svetlana; Tretiak, Sergei; Sykora, Milan; Albert, Victor; Badaeva, Ekaterina; Koposov, Alexey

    2008-01-01

    New photovoltaic and photocatalysis applications have been recently proposed based on the hybrid Ru(II)-bipyridine-complex/semiconductor quantum dot systems. In order to attach the Ru(II) complex to the surface of a semiconductor, a linking bridge -- a carboxyl group -- needs to be added to one or two of the 2,2'-bipyridine (bpy) ligands. Such changes in the ligand structure affect electronic and optical properties and, consequently, the charge transfer reactivity of Ru(II)-systems. In this study, we analyze the effects brought by functionalization of bipyridine ligands with the methyl, carboxyl, and carboxilate groups on the electronic structure and optical response of the [Ru(bpy){sub 3}]{sup 2+} complex. First principle calculations based on density functional theory (DFT) and time dependent DFT (TDDFT) are used to simulate the ground and excited-state properties, respectively, of functionalized Ru-complexes in the gas phase and acetonitrile solution. In addition, an effective Frenkel exciton model is used to explain the optical activity and splitting patterns of the low-energy excited states in all molecules. All theoretical results nicely complement and allow for detailed interpretation of experimental absorption spectra of Ru-complexes that have been done in parallel with our theoretical investigations. We found that the carboxyl group breaks the degeneracy of two low-energy optically bright excited states and red-shifts the absorption spectrum, while leaves ionization and affinity energies of complexes almost unchanged. Experimental studies show that deprotonation of the carboxyl group in the Ru-complexes results in a slight blue shift and decrease of oscillator strengths of the low energy absorption peaks. Comparison of experimental and theoretical linear response spectra of deprotonated complexes demonstrate strong agreement if the theoretical calculations are performed with the addition of a dielectric continuum model. A polar solvent is found to play an

  18. Imaging samples in silica aerogel using an experimental point spread function.

    PubMed

    White, Amanda J; Ebel, Denton S

    2015-02-01

    Light microscopy is a powerful tool that allows for many types of samples to be examined in a rapid, easy, and nondestructive manner. Subsequent image analysis, however, is compromised by distortion of signal by instrument optics. Deconvolution of images prior to analysis allows for the recovery of lost information by procedures that utilize either a theoretically or experimentally calculated point spread function (PSF). Using a laser scanning confocal microscope (LSCM), we have imaged whole impact tracks of comet particles captured in silica aerogel, a low density, porous SiO2 solid, by the NASA Stardust mission. In order to understand the dynamical interactions between the particles and the aerogel, precise grain location and track volume measurement are required. We report a method for measuring an experimental PSF suitable for three-dimensional deconvolution of imaged particles in aerogel. Using fluorescent beads manufactured into Stardust flight-grade aerogel, we have applied a deconvolution technique standard in the biological sciences to confocal images of whole Stardust tracks. The incorporation of an experimentally measured PSF allows for better quantitative measurements of the size and location of single grains in aerogel and more accurate measurements of track morphology. PMID:25517515

  19. Experimental Measurements and Density Functional Theory Calculations of Continuum Lowering in Strongly Coupled Plasmas

    NASA Astrophysics Data System (ADS)

    Vinko, Sam

    2014-10-01

    An accurate description of the ionization potential depression (IPD) of ions in plasmas due to their interaction with the environment is a fundamental problem in plasma physics, playing a key role in determining the ionization balance, charge state distribution, opacity and plasma equation of state. Here I present the first experimental investigation of the IPD as a function of ionic charge state in a range of dense Mg, Al and Si plasmas, using the Linac Coherent Light Source X-ray free-electron laser. The measurements show significantly larger IPDs than are predicted by the most commonly used models, such as that of Stewart-Pyatt, or the ion-sphere model of Zimmerman-More. Instead, plasma simulations using finite-temperature density functional theory with excited-state projector augmented-wave potentials show excellent agreement with the experimental results and explain the stronger-than-expected continuum lowering through the electronic structure of the valence states in these strong-coupling conditions, which retain much of their atomic characteristics close to the ion core regions. These results have a profound impact on the understanding and modelling of plasmas over a wide range of warm- and hot-dense matter conditions.

  20. Comparison between Theoretical Calculation and Experimental Results of Excitation Functions for Production of Relevant Biomedical Radionuclides

    NASA Astrophysics Data System (ADS)

    Menapace, E.; Birattari, C.; Bonardi, M. L.; Groppi, F.; Morzenti, S.; Zona, C.

    2005-05-01

    The radionuclide production for biomedical applications has been brought up in the years, as a special nuclear application, at INFN LASA Laboratory, particularly in co-operation with the JRC-Ispra of EC. Mainly scientific aspects concerning radiation detection and the relevant instruments, the measurements of excitation functions of the involved nuclear reactions, the requested radiochemistry studies and further applications have been investigated. On the side of the nuclear data evaluations, based on nuclear model calculations and critically selected experimental data, the appropriate competence has been developed at ENEA Division for Advanced Physics Technologies. A series of high specific activity accelerator-produced radionuclides in no-carrier-added (NCA) form, for uses in metabolic radiotherapy and for PET radiodiagnostics, are investigated. In this work, last revised measurements and model calculations are reviewed for excitation functions of natZn(d,X)64Cu, 66Ga reactions, referring to irradiation experiments at K=38 variable energy Cyclotron of JRC-Ispra. Concerning the reaction data for producing 186gRe and 211At/211gPo (including significant emission spectra) and 210At, most recent and critically selected experimental results are considered and discussed in comparison with model calculations paying special care to pre-equilibrium effects estimate and to the appropriate overall parameterization. Model calculations are presented for 226Ra(p,2n)225Ac reaction, according to the working program of the ongoing IAEA CRP on the matter.

  1. Acidity of the amidoxime functional group in aqueous solution: a combined experimental and computational study.

    PubMed

    Mehio, Nada; Lashely, Mark A; Nugent, Joseph W; Tucker, Lyndsay; Correia, Bruna; Do-Thanh, Chi-Linh; Dai, Sheng; Hancock, Robert D; Bryantsev, Vyacheslav S

    2015-02-26

    Poly(acrylamidoxime) adsorbents are often invoked in discussions of mining uranium from seawater. While the amidoxime-uranyl chelation mode has been established, a number of essential binding constants remain unclear. This is largely due to the wide range of conflicting pK(a) values that have been reported for the amidoxime functional group. To resolve this existing controversy we investigated the pK(a) values of the amidoxime functional group using a combination of experimental and computational methods. Experimentally, we used spectroscopic titrations to measure the pK(a) values of representative amidoximes, acetamidoxime, and benzamidoxime. Computationally, we report on the performance of several protocols for predicting the pK(a) values of aqueous oxoacids. Calculations carried out at the MP2 or M06-2X levels of theory combined with solvent effects calculated using the SMD model provide the best overall performance, with a root-mean-square deviation of 0.46 pK(a) units and 0.45 pK(a) units, respectively. Finally, we employ our two best methods to predict the pK(a) values of promising, uncharacterized amidoxime ligands, which provides a convenient means for screening suitable amidoxime monomers for future generations of poly(acrylamidoxime) adsorbents. PMID:25621618

  2. Urban artificial light emission function determined experimentally using night sky images

    NASA Astrophysics Data System (ADS)

    Solano Lamphar, Héctor Antonio; Kocifaj, Miroslav

    2016-09-01

    To date, diverse approximations have been developed to interpret the radiance of a night sky due to light emissions from ground-based light sources. The radiant intensity distribution as a function of zenith angle is one of the most unknown properties because of the collective effects of all artificial, private and public lights. The emission function (EF) is, however, a key property in modeling the skyglow under arbitrary conditions, and thus it is equally required by modelers, light pollution researchers, and also experimentalists who are using specialized devices to study the diffuse light of a night sky. In this paper, we present the second generation of a dedicated measuring system intended for routine monitoring of a night sky in any region. The experimental technology we have developed is used to interpret clear sky radiance data recorded at a set of discrete distances from a town (or city) with the aim to infer the fraction of upwardly emitted light (F), that is a parameter scaling the bulk EF. The retrieval of the direct upward emissions has been improved by introducing a weighting factor that is used to eliminate imperfections of experimental data and thus to make the computation of F more stable when processing the radiance data taken at two adjacent measuring points. The field experiments made in three Mexican cities are analyzed and the differences found are discussed.

  3. Comparison between Theoretical Calculation and Experimental Results of Excitation Functions for Production of Relevant Biomedical Radionuclides

    SciTech Connect

    Menapace, E.; Birattari, C.; Bonardi, M.L.; Groppi, F.; Morzenti, S.; Zona, C.

    2005-05-24

    The radionuclide production for biomedical applications has been brought up in the years, as a special nuclear application, at INFN LASA Laboratory, particularly in co-operation with the JRC-Ispra of EC. Mainly scientific aspects concerning radiation detection and the relevant instruments, the measurements of excitation functions of the involved nuclear reactions, the requested radiochemistry studies and further applications have been investigated. On the side of the nuclear data evaluations, based on nuclear model calculations and critically selected experimental data, the appropriate competence has been developed at ENEA Division for Advanced Physics Technologies. A series of high specific activity accelerator-produced radionuclides in no-carrier-added (NCA) form, for uses in metabolic radiotherapy and for PET radiodiagnostics, are investigated. In this work, last revised measurements and model calculations are reviewed for excitation functions of natZn(d,X)64Cu, 66Ga reactions, referring to irradiation experiments at K=38 variable energy Cyclotron of JRC-Ispra. Concerning the reaction data for producing 186gRe and 211At/211gPo (including significant emission spectra) and 210At, most recent and critically selected experimental results are considered and discussed in comparison with model calculations paying special care to pre-equilibrium effects estimate and to the appropriate overall parameterization. Model calculations are presented for 226Ra(p,2n)225Ac reaction, according to the working program of the ongoing IAEA CRP on the matter.

  4. A photoemission model for low work function coated metal surfaces and its experimental validation

    NASA Astrophysics Data System (ADS)

    Jensen, Kevin L.; Feldman, Donald W.; Moody, Nathan A.; O'Shea, Patrick G.

    2006-06-01

    Photocathodes are a critical component many linear accelerator based light sources. The development of a custom-engineered photocathode based on low work function coatings requires an experimentally validated photoemission model that accounts the complexity of the emission process. We have developed a time-dependent model accounting for the effects of laser heating and thermal propagation on photoemission. It accounts for surface conditions (coating, field enhancement, and reflectivity), laser parameters (duration, intensity, and wavelength), and material characteristics (reflectivity, laser penetration depth, and scattering rates) to predict current distribution and quantum efficiency (QE) as a function of wavelength. The model is validated by (i) experimental measurements of the QE of cesiated surfaces, (ii) the QE and performance of commercial dispenser cathodes (B, M, and scandate), and (iii) comparison to QE values reported in the literature for bare metals and B-type dispenser cathodes, all for various wavelengths. Of particular note is that the highest QE for a commercial (M-type) dispenser cathode found here was measured to be 0.22% at 266 nm, and is projected to be 3.5 times larger for a 5 ps pulse delivering 0.6 mJ/cm2 under a 50 MV/m field.

  5. Regulation of cellular function via electromagnetic field frequency and extracellular environment: A theoretical- experimental approach

    NASA Astrophysics Data System (ADS)

    Taghian, Toloo; Sheikh, Abdul; Narmoneva, Daria; Kogan, Andrei

    2015-03-01

    Application of external electric field (EF) as a non-pharmacological, non-invasive tool to control cell function is of great therapeutic interest. We developed a theoretical-experimental approach to investigate the biophysical mechanisms of EF interaction with cells in electrode-free physiologically-relevant configuration. Our numerical results demonstrated that EF frequency is the major parameter to control cell response to EF. Non-oscillating or low-frequency EF leads to charge accumulation on the cell surface membrane that may mediate membrane initiated cell responses. In contrast, high-frequency EF penetrates the cell membrane and reaches cell cytoplasm, where it may directly activate intracellular responses. The theoretical predictions were confirmed in our experimental studies of the effects of applied EF on vascular cell function. Results show that non-oscillating EF increases vascular endothelial growth factor (VEGF) expression while field polarity controls cell adhesion rate. High-frequency, but not low frequency, EF provides differential regulation of cytoplasmic focal adhesion kinase and VEGF expression depending on the substrate, with increased expression in cells cultured on RGD-rich synthetic hydrogels, and decreased expression for matrigel culture. The authors acknowledge the financial support from the NSF (DMR-1206784 & DMR-0804199 to AK); the NIH (1R21 DK078814-01A1 to DN) and the University of Cincinnati (Interdisciplinary Faculty Research Support Grant to DN and AK).

  6. Sparing of muscle mass and function by passive loading in an experimental intensive care unit model.

    PubMed

    Renaud, Guillaume; Llano-Diez, Monica; Ravara, Barbara; Gorza, Luisa; Feng, Han-Zhong; Jin, Jian-Ping; Cacciani, Nicola; Gustafson, Ann-Marie; Ochala, Julien; Corpeno, Rebeca; Li, Meishan; Hedström, Yvette; Ford, G Charles; Nair, K Sreekumaran; Larsson, Lars

    2013-03-01

    The response to mechanical stimuli, i.e., tensegrity, plays an important role in regulating cell physiological and pathophysiological function, and the mechanical silencing observed in intensive care unit (ICU) patients leads to a severe and specific muscle wasting condition. This study aims to unravel the underlying mechanisms and the effects of passive mechanical loading on skeletal muscle mass and function at the gene, protein and cellular levels. A unique experimental rat ICU model has been used allowing long-term (weeks) time-resolved analyses of the effects of standardized unilateral passive mechanical loading on skeletal muscle size and function and underlying mechanisms. Results show that passive mechanical loading alleviated the muscle wasting and the loss of force-generation associated with the ICU intervention, resulting in a doubling of the functional capacity of the loaded versus the unloaded muscles after a 2-week ICU intervention. We demonstrate that the improved maintenance of muscle mass and function is probably a consequence of a reduced oxidative stress revealed by lower levels of carbonylated proteins, and a reduced loss of the molecular motor protein myosin. A complex temporal gene expression pattern, delineated by microarray analysis, was observed with loading-induced changes in transcript levels of sarcomeric proteins, muscle developmental processes, stress response, extracellular matrix/cell adhesion proteins and metabolism. Thus, the results from this study show that passive mechanical loading alleviates the severe negative consequences on muscle size and function associated with the mechanical silencing in ICU patients, strongly supporting early and intense physical therapy in immobilized ICU patients. PMID:23266938

  7. Effects of experimental cardiac volume loading on left atrial phasic function in healthy dogs.

    PubMed

    Osuga, Tatsuyuki; Nakamura, Kensuke; Morita, Tomoya; Nisa, Khoirun; Yokoyama, Nozomu; Sasaki, Noboru; Morishita, Keitaro; Ohta, Hiroshi; Takiguchi, Mitsuyoshi

    2016-09-01

    OBJECTIVE To elucidate the relationship between acute volume overload and left atrial phasic function in healthy dogs. ANIMALS 6 healthy Beagles. PROCEDURES Dogs were anesthetized. A Swan-Ganz catheter was placed to measure mean pulmonary capillary wedge pressure (PCWP). Cardiac preload was increased by IV infusion with lactated Ringer solution at 150 mL/kg/h for 90 minutes. Transthoracic echocardiography was performed before (baseline) and at 15, 30, 45, 60, 75, and 90 minutes after volume loading began. At each echocardiographic assessment point, apical 4-chamber images were recorded and analyzed to derive time-left atrial area curves. Left atrial total (for reservoir function), passive (for conduit function), and active (for booster-pump function) fractional area changes were calculated from the curves. RESULTS Volume overload resulted in a significant increase from baseline in PCWP from 15 to 90 minutes after volume loading began. All fractional area changes at 15 to 90 minutes were significantly increased from baseline. In multiple regression analysis, quadratic regression models were better fitted to the relationships between PCWP and each of the total and active fractional area changes than were linear regression models. A linear regression model was better fitted to the relationship between PCWP and passive fractional area change. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that left atrial phasic function assessed on the basis of left atrial phasic areas was enhanced during experimental cardiac volume loading in healthy dogs. The effect of volume load should be considered when evaluating left atrial phasic function by indices derived from left atrial phasic sizes. PMID:27580106

  8. Anatomic and Functional Connectivity Relationship in Autistic Children During Three Different Experimental Conditions.

    PubMed

    Machado, Calixto; Rodríguez, Rafael; Estévez, Mario; Leisman, Gerry; Melillo, Robert; Chinchilla, Mauricio; Portela, Liana

    2015-10-01

    A group of 21 autistic children were studied for determining the relationship between the anatomic (AC) versus functional (FC) connectivity, considering short-range and long-range brain networks. AC was assessed by the DW-MRI technique and FC by EEG coherence calculation, in three experimental conditions: basal, watching a popular cartoon with audio (V-A), and with muted audio track (VwA). For short-range connections, basal records, statistical significant correlations were found for all EEG bands in the left hemisphere, but no significant correlations were found for fast EEG frequencies in the right hemisphere. For the V-A condition, significant correlations were mainly diminished for the left hemisphere; for the right hemisphere, no significant correlations were found for the fast EEG frequency bands. For the VwA condition, significant correlations for the rapid EEG frequencies mainly disappeared for the right hemisphere. For long-range connections, basal records showed similar correlations for both hemispheres. For the right hemisphere, significant correlations incremented to all EEG bands for the V-A condition, but these significant correlations disappeared for the fast EEG frequencies in the VwA condition. It appears that in a resting-state condition, AC is better associated with functional connectivity for short-range connections in the left hemisphere. The V-A experimental condition enriches the AC and FC association for long-range connections in the right hemisphere. This might be related to an effective connectivity improvement due to full video stimulation (visual and auditory). An impaired audiovisual interaction in the right hemisphere might explain why significant correlations disappeared for the fast EEG frequencies in the VwA experimental condition. PMID:26050707

  9. Functional Magnetic Resonance Imaging of Rats with Experimental Autoimmune Encephalomyelitis Reveals Brain Cortex Remodeling

    PubMed Central

    Tambalo, Stefano; Peruzzotti-Jametti, Luca; Rigolio, Roberta; Fiorini, Silvia; Bontempi, Pietro; Mallucci, Giulia; Balzarotti, Beatrice; Marmiroli, Paola; Sbarbati, Andrea; Cavaletti, Guido

    2015-01-01

    Cortical reorganization occurring in multiple sclerosis (MS) patients is thought to play a key role in limiting the effect of structural tissue damage. Conversely, its exhaustion may contribute to the irreversible disability that accumulates with disease progression. Several aspects of MS-related cortical reorganization, including the overall functional effect and likely modulation by therapies, still remain to be elucidated. The aim of this work was to assess the extent of functional cortical reorganization and its brain structural/pathological correlates in Dark Agouti rats with experimental autoimmune encephalomyelitis (EAE), a widely accepted preclinical model of chronic MS. Morphological and functional MRI (fMRI) were performed before disease induction and during the relapsing and chronic phases of EAE. During somatosensory stimulation of the right forepaw, fMRI demonstrated that cortical reorganization occurs in both relapsing and chronic phases of EAE with increased activated volume and decreased laterality index versus baseline values. Voxel-based morphometry demonstrated gray matter (GM) atrophy in the cerebral cortex, and both GM and white matter atrophy were assessed by ex vivo pathology of the sensorimotor cortex and corpus callosum. Neuroinflammation persisted in the relapsing and chronic phases, with dendritic spine density in the layer IV sensory neurons inversely correlating with the number of cluster of differentiation 45-positive inflammatory lesions. Our work provides an innovative experimental platform that may be pivotal for the comprehension of key mechanisms responsible for the accumulation of irreversible brain damage and for the development of innovative therapies to reduce disability in EAE/MS. SIGNIFICANCE STATEMENT Since the early 2000s, functional MRI (fMRI) has demonstrated profound modifications in the recruitment of cortical areas during motor, cognitive, and sensory tasks in multiple sclerosis (MS) patients. Experimental autoimmune

  10. Undergraduate teaching of neurosurgery - what is the current practice in the UK and is there a need for improvement?

    PubMed

    Whitehouse, Kathrin J; Moore, Anne J

    2015-01-01

    There has been concern that the move towards generalism means that specialties, such as neurosurgery, are being pushed out of the undergraduate syllabus. Surveys were created, along with the Society of British Neurological Surgeons, and sent to medical school representatives (MSRs) and neurosurgery programme directors (NPDs) in the United Kingdom (UK). 60% of MSRs and 71% of NPDs responded. Neurosurgical topics were taught by a variety of specialties, and in one medical school, a MSR said that neurosurgery was not taught at all. 83% of MSRs and 80% of NPDs said that neurosurgeons should be more involved in undergraduate education, with 70% of NPDs saying that their unit would be willing to have increased involvement. All NPDs, but only 72% of MSRs, said that neurosurgery should be taught in medical school. Those MSRs who disagreed opined that it was a postgraduate subject, and could be difficult to engage all students. The majority of MSRs and NPDs thought that neurosurgery guidelines would be useful. The most popular forms of guidance were in the forms of curriculum/guidelines, website and powerpoint presentations. It is therefore recommended that neurosurgeons, under the umbrella of the Society of British Neurological Surgeons, create national guidelines for the teaching of undergraduate students; to aid their educational colleagues and ensure that accurate, standardised teaching occurs. Care must be taken not to be over-prescriptive in these endeavours. PMID:26083138

  11. Acidity of the amidoxime functional group in aqueous solution. A combined experimental and computational study

    SciTech Connect

    Mehio, Nada; Lashely, Mark A.; Nugent, Joseph W.; Tucker, Lyndsay; Correia, Bruna; Do-Thanh, Chi-Linh; Dai, Sheng; Hancock, Robert D.; Bryantsev, Vyacheslav S.

    2015-01-26

    Poly(acrylamidoxime) adsorbents are often invoked in discussions of mining uranium from seawater. It has been demonstrated repeatedly in the literature that the success of these materials is due to the amidoxime functional group. While the amidoxime-uranyl chelation mode has been established, a number of essential binding constants remain unclear. This is largely due to the wide range of conflicting pKa values that have been reported for the amidoxime functional group in the literature. To resolve this existing controversy we investigated the pKa values of the amidoxime functional group using a combination of experimental and computational methods. Experimentally, we used spectroscopic titrations to measure the pKa values of representative amidoximes, acetamidoxime and benzamidoxime. Computationally, we report on the performance of several protocols for predicting the pKa values of aqueous oxoacids. Calculations carried out at the MP2 or M06-2X levels of theory combined with solvent effects calculated using the SMD model provide the best overall performance with a mean absolute error of 0.33 pKa units and 0.35 pKa units, respectively, and a root mean square deviation of 0.46 pKa units and 0.45 pKa units, respectively. Finally, we employ our two best methods to predict the pKa values of promising, uncharacterized amidoxime ligands. Hence, our study provides a convenient means for screening suitable amidoxime monomers for future generations of poly(acrylamidoxime) adsorbents used to mine uranium from seawater.

  12. Acidity of the amidoxime functional group in aqueous solution. A combined experimental and computational study

    DOE PAGESBeta

    Mehio, Nada; Lashely, Mark A.; Nugent, Joseph W.; Tucker, Lyndsay; Correia, Bruna; Do-Thanh, Chi-Linh; Dai, Sheng; Hancock, Robert D.; Bryantsev, Vyacheslav S.

    2015-01-26

    Poly(acrylamidoxime) adsorbents are often invoked in discussions of mining uranium from seawater. It has been demonstrated repeatedly in the literature that the success of these materials is due to the amidoxime functional group. While the amidoxime-uranyl chelation mode has been established, a number of essential binding constants remain unclear. This is largely due to the wide range of conflicting pKa values that have been reported for the amidoxime functional group in the literature. To resolve this existing controversy we investigated the pKa values of the amidoxime functional group using a combination of experimental and computational methods. Experimentally, we used spectroscopicmore » titrations to measure the pKa values of representative amidoximes, acetamidoxime and benzamidoxime. Computationally, we report on the performance of several protocols for predicting the pKa values of aqueous oxoacids. Calculations carried out at the MP2 or M06-2X levels of theory combined with solvent effects calculated using the SMD model provide the best overall performance with a mean absolute error of 0.33 pKa units and 0.35 pKa units, respectively, and a root mean square deviation of 0.46 pKa units and 0.45 pKa units, respectively. Finally, we employ our two best methods to predict the pKa values of promising, uncharacterized amidoxime ligands. Hence, our study provides a convenient means for screening suitable amidoxime monomers for future generations of poly(acrylamidoxime) adsorbents used to mine uranium from seawater.« less

  13. Investment in constitutive immune function by North American elk experimentally maintained at two different population densities.

    PubMed

    Downs, Cynthia J; Stewart, Kelley M; Dick, Brian L

    2015-01-01

    Natural selection favors individuals that respond with effective and appropriate immune responses to macro or microparasites. Animals living in populations close to ecological carrying capacity experience increased intraspecific competition, and as a result are often in poor nutritional condition. Nutritional condition, in turn, affects the amount of endogenous resources that are available for investment in immune function. Our objective was to understand the relationship between immune function and density dependence mediated by trade-offs between immune function, nutritional condition, and reproduction. To determine how immune function relates to density-dependent processes, we quantified bacteria killing ability, hemolytic-complement activity, and nutritional condition of North American elk (Cervus elaphus) from populations maintained at experimentally high- and low-population densities. When compared with elk from the low-density population, those from the high-density population had higher bacteria killing ability and hemolytic-complement activity despite their lower nutritional condition. Similarly, when compared with adults, yearlings had higher bacteria killing ability, higher hemolytic-complement activity, and lower nutritional condition. Pregnancy status and lactational status did not change either measure of constitutive immunity. Density-dependent processes affected both nutritional condition and investment in constitutive immune function. Although the mechanism for how density affects immunity is ambiguous, we hypothesize two possibilities: (i) individuals in higher population densities and in poorer nutritional condition invested more into constitutive immune defenses, or (ii) had higher parasite loads causing higher induced immune responses. Those explanations are not mutually exclusive, and might be synergistic, but overall our results provide stronger support for the hypothesis that animals in poorer nutritional condition invest more in

  14. Investment in Constitutive Immune Function by North American Elk Experimentally Maintained at Two Different Population Densities

    PubMed Central

    Downs, Cynthia J.; Stewart, Kelley M.; Dick, Brian L.

    2015-01-01

    Natural selection favors individuals that respond with effective and appropriate immune responses to macro or microparasites. Animals living in populations close to ecological carrying capacity experience increased intraspecific competition, and as a result are often in poor nutritional condition. Nutritional condition, in turn, affects the amount of endogenous resources that are available for investment in immune function. Our objective was to understand the relationship between immune function and density dependence mediated by trade-offs between immune function, nutritional condition, and reproduction. To determine how immune function relates to density-dependent processes, we quantified bacteria killing ability, hemolytic-complement activity, and nutritional condition of North American elk (Cervus elaphus) from populations maintained at experimentally high- and low-population densities. When compared with elk from the low-density population, those from the high-density population had higher bacteria killing ability and hemolytic-complement activity despite their lower nutritional condition. Similarly, when compared with adults, yearlings had higher bacteria killing ability, higher hemolytic-complement activity, and lower nutritional condition. Pregnancy status and lactational status did not change either measure of constitutive immunity. Density-dependent processes affected both nutritional condition and investment in constitutive immune function. Although the mechanism for how density affects immunity is ambiguous, we hypothesize two possibilities: (i) individuals in higher population densities and in poorer nutritional condition invested more into constitutive immune defenses, or (ii) had higher parasite loads causing higher induced immune responses. Those explanations are not mutually exclusive, and might be synergistic, but overall our results provide stronger support for the hypothesis that animals in poorer nutritional condition invest more in

  15. An Experimental Investigation of the Functional Hypothesis and Evolutionary Advantage of Stone-Tipped Spears

    PubMed Central

    Wilkins, Jayne; Schoville, Benjamin J.; Brown, Kyle S.

    2014-01-01

    Stone-tipped weapons were a significant innovation for Middle Pleistocene hominins. Hafted hunting technology represents the development of new cognitive and social learning mechanisms within the genus Homo, and may have provided a foraging advantage over simpler forms of hunting technology, such as a sharpened wooden spear. However, the nature of this foraging advantage has not been confirmed. Experimental studies and ethnographic reports provide conflicting results regarding the relative importance of the functional, economic, and social roles of hafted hunting technology. The controlled experiment reported here was designed to test the functional hypothesis for stone-tipped weapons using spears and ballistics gelatin. It differs from previous investigations of this type because it includes a quantitative analysis of wound track profiles and focuses specifically on hand-delivered spear technology. Our results do not support the hypothesis that tipped spears penetrate deeper than untipped spears. However, tipped spears create a significantly larger inner wound cavity that widens distally. This inner wound cavity is analogous to the permanent wound cavity in ballistics research, which is considered the key variable affecting the relative ‘stopping power’ or ‘killing power’ of a penetrating weapon. Tipped spears conferred a functional advantage to Middle Pleistocene hominins, potentially affecting the frequency and regularity of hunting success with important implications for human adaptation and life history. PMID:25162397

  16. An experimental study of the accuracy in measurement of modulation transfer function using an edge method

    NASA Astrophysics Data System (ADS)

    Lee, Dong-Hoon; Kim, Ye-seul; Park, Hye-Suk; Lee, Young-Jin; Kim, Hee-Joung

    2015-03-01

    Image evaluation is necessary in digital radiography (DR) which is widely used in medical imaging. Among parameters of image evaluation, modulation transfer function (MTF) is the important factor in the field of medical imaging and necessary to obtain detective quantum efficiency (DQE) which represents overall performance of the detector signal-to-noise ratio. However, the accurate measurement of MTF is still not easy because of geometric effect, electric noise, quantum noise, and truncation error. Therefore, in order to improve accuracy of MTF, four experimental methods were tested in this study such as changing the tube current, applying smoothing method in edge spread function (ESF), adjusting line spread function (LSF) range, and changing tube angle. Our results showed that MTF's fluctuation was decreased by high tube current and smoothing method. However, tube current should not exceed detector saturation and smoothing in ESF causes a distortion in ESF and MTF. In addition, decreasing LSF range diminished fluctuation and the number of sampling in MTF and high tube angle generates degradation in MTF. Based on these results, excessively low tube current and the smoothing method should be avoided. Also, optimal range of LSF considering reduction of fluctuation and the number of sampling in MTF was necessary and precise tube angle is essential to obtain an accurate MTF. In conclusion, our results demonstrated that accurate MTF can be acquired.

  17. An experimental investigation of the functional hypothesis and evolutionary advantage of stone-tipped spears.

    PubMed

    Wilkins, Jayne; Schoville, Benjamin J; Brown, Kyle S

    2014-01-01

    Stone-tipped weapons were a significant innovation for Middle Pleistocene hominins. Hafted hunting technology represents the development of new cognitive and social learning mechanisms within the genus Homo, and may have provided a foraging advantage over simpler forms of hunting technology, such as a sharpened wooden spear. However, the nature of this foraging advantage has not been confirmed. Experimental studies and ethnographic reports provide conflicting results regarding the relative importance of the functional, economic, and social roles of hafted hunting technology. The controlled experiment reported here was designed to test the functional hypothesis for stone-tipped weapons using spears and ballistics gelatin. It differs from previous investigations of this type because it includes a quantitative analysis of wound track profiles and focuses specifically on hand-delivered spear technology. Our results do not support the hypothesis that tipped spears penetrate deeper than untipped spears. However, tipped spears create a significantly larger inner wound cavity that widens distally. This inner wound cavity is analogous to the permanent wound cavity in ballistics research, which is considered the key variable affecting the relative 'stopping power' or 'killing power' of a penetrating weapon. Tipped spears conferred a functional advantage to Middle Pleistocene hominins, potentially affecting the frequency and regularity of hunting success with important implications for human adaptation and life history. PMID:25162397

  18. Liquid contact resonance atomic force microscopy via experimental reconstruction of the hydrodynamic function

    NASA Astrophysics Data System (ADS)

    Tung, Ryan C.; Killgore, Jason P.; Hurley, Donna C.

    2014-06-01

    We present a method to correct for surface-coupled inertial and viscous fluid loading forces in contact resonance (CR) atomic force microscopy (AFM) experiments performed in liquid. Based on analytical hydrodynamic theory, the method relies on experimental measurements of the AFM cantilever's free resonance peaks near the sample surface. The free resonance frequencies and quality factors in both air and liquid allow reconstruction of a continuous hydrodynamic function that can be used to adjust the CR data in liquid. Validation experiments utilizing thermally excited free and in-contact spectra were performed to assess the accuracy of our approach. Results show that the method recovers the air frequency values within approximately 6%. Knowledge of fluid loading forces allows current CR analysis techniques formulated for use in air and vacuum environments to be applied to liquid environments. Our technique greatly extends the range of measurement environments available to CR-AFM.

  19. Liquid contact resonance atomic force microscopy via experimental reconstruction of the hydrodynamic function

    SciTech Connect

    Tung, Ryan C. Killgore, Jason P.; Hurley, Donna C.

    2014-06-14

    We present a method to correct for surface-coupled inertial and viscous fluid loading forces in contact resonance (CR) atomic force microscopy (AFM) experiments performed in liquid. Based on analytical hydrodynamic theory, the method relies on experimental measurements of the AFM cantilever's free resonance peaks near the sample surface. The free resonance frequencies and quality factors in both air and liquid allow reconstruction of a continuous hydrodynamic function that can be used to adjust the CR data in liquid. Validation experiments utilizing thermally excited free and in-contact spectra were performed to assess the accuracy of our approach. Results show that the method recovers the air frequency values within approximately 6%. Knowledge of fluid loading forces allows current CR analysis techniques formulated for use in air and vacuum environments to be applied to liquid environments. Our technique greatly extends the range of measurement environments available to CR-AFM.

  20. An experimental approach to study the function of mitochondria in cardiomyopathy

    PubMed Central

    Chung, Youn Wook; Kang, Seok-Min

    2015-01-01

    Cardiomyopathy is an inherited or acquired disease of the myocardium, which can result in severe ventricular dysfunction. Mitochondrial dysfunction is involved in the pathological process of cardiomyopathy. Many dysfunctions in cardiac mitochondria are consequences of mutations in nuclear or mitochondrial DNA followed by alterations in transcriptional regulation, mitochondrial protein function, and mitochondrial dynamics and energetics, presenting with associated multisystem mitochondrial disorders. To ensure correct diagnosis and optimal management of mitochondrial dysfunction in cardiomyopathy caused by multiple pathogenesis, multidisciplinary approaches are required, and to integrate between clinical and basic sciences, ideal translational models are needed. In this review, we will focus on experimental models to provide insights into basic mitochondrial physiology and detailed underlying mechanisms of cardiomyopathy and current mitochondria-targeted therapies for cardiomyopathy. [BMB Reports 2015; 48(10): 541-548] PMID:26198095

  1. Experimental Energy Levels and Partition Function of the 12C2 Molecule

    NASA Astrophysics Data System (ADS)

    Furtenbacher, Tibor; Szabó, István; Császár, Attila G.; Bernath, Peter F.; Yurchenko, Sergei N.; Tennyson, Jonathan

    2016-06-01

    The carbon dimer, the 12C2 molecule, is ubiquitous in astronomical environments. Experimental-quality rovibronic energy levels are reported for 12C2, based on rovibronic transitions measured for and among its singlet, triplet, and quintet electronic states, reported in 42 publications. The determination utilizes the Measured Active Rotational-Vibrational Energy Levels (MARVEL) technique. The 23,343 transitions measured experimentally and validated within this study determine 5699 rovibronic energy levels, 1325, 4309, and 65 levels for the singlet, triplet, and quintet states investigated, respectively. The MARVEL analysis provides rovibronic energies for six singlet, six triplet, and two quintet electronic states. For example, the lowest measurable energy level of the {{a}}{}3{{{\\Pi }}}{{u}} state, corresponding to the J = 2 total angular momentum quantum number and the F 1 spin-multiplet component, is 603.817(5) cm‑1. This well-determined energy difference should facilitate observations of singlet–triplet intercombination lines, which are thought to occur in the interstellar medium and comets. The large number of highly accurate and clearly labeled transitions that can be derived by combining MARVEL energy levels with computed temperature-dependent intensities should help a number of astrophysical observations as well as corresponding laboratory measurements. The experimental rovibronic energy levels, augmented, where needed, with ab initio variational ones based on empirically adjusted and spin–orbit coupled potential energy curves obtained using the Duo code, are used to obtain a highly accurate partition function, and related thermodynamic data, for 12C2 up to 4000 K.

  2. Current Applications and Future Perspectives of the Use of 3D Printing in Anatomical Training and Neurosurgery

    PubMed Central

    Baskaran, Vivek; Štrkalj, Goran; Štrkalj, Mirjana; Di Ieva, Antonio

    2016-01-01

    3D printing is a form of rapid prototyping technology, which has led to innovative new applications in biomedicine. It facilitates the production of highly accurate three dimensional objects from substrate materials. The inherent accuracy and other properties of 3D printing have allowed it to have exciting applications in anatomy education and surgery, with the specialty of neurosurgery having benefited particularly well. This article presents the findings of a literature review of the Pubmed and Web of Science databases investigating the applications of 3D printing in anatomy and surgical education, and neurosurgery. A number of applications within these fields were found, with many significantly improving the quality of anatomy and surgical education, and the practice of neurosurgery. They also offered advantages over existing approaches and practices. It is envisaged that the number of useful applications will rise in the coming years, particularly as the costs of this technology decrease and its uptake rises. PMID:27445707

  3. Current Applications and Future Perspectives of the Use of 3D Printing in Anatomical Training and Neurosurgery.

    PubMed

    Baskaran, Vivek; Štrkalj, Goran; Štrkalj, Mirjana; Di Ieva, Antonio

    2016-01-01

    3D printing is a form of rapid prototyping technology, which has led to innovative new applications in biomedicine. It facilitates the production of highly accurate three dimensional objects from substrate materials. The inherent accuracy and other properties of 3D printing have allowed it to have exciting applications in anatomy education and surgery, with the specialty of neurosurgery having benefited particularly well. This article presents the findings of a literature review of the Pubmed and Web of Science databases investigating the applications of 3D printing in anatomy and surgical education, and neurosurgery. A number of applications within these fields were found, with many significantly improving the quality of anatomy and surgical education, and the practice of neurosurgery. They also offered advantages over existing approaches and practices. It is envisaged that the number of useful applications will rise in the coming years, particularly as the costs of this technology decrease and its uptake rises. PMID:27445707

  4. Kinetic energies to analyze the experimental auger electron spectra by density functional theory calculations

    NASA Astrophysics Data System (ADS)

    Endo, Kazunaka

    2016-02-01

    In the Auger electron spectra (AES) simulations, we define theoretical modified kinetic energies of AES in the density functional theory (DFT) calculations. The modified kinetic energies correspond to two final-state holes at the ground state and at the transition-state in DFT calculations, respectively. This method is applied to simulate Auger electron spectra (AES) of 2nd periodic atom (Li, Be, B, C, N, O, F)-involving substances (LiF, beryllium, boron, graphite, GaN, SiO2, PTFE) by deMon DFT calculations using the model molecules of the unit cell. Experimental KVV (valence band electrons can fill K-shell core holes or be emitted during KVV-type transitions) AES of the (Li, O) atoms in the substances agree considerably well with simulation of AES obtained with the maximum kinetic energies of the atoms, while, for AES of LiF, and PTFE substance, the experimental F KVV AES is almost in accordance with the spectra from the transitionstate kinetic energy calculations.

  5. Experimental Determination of the Electric Dipole Moment Function of the X Pi-2 Hydroxyl Radical

    NASA Technical Reports Server (NTRS)

    Chackerian, C., Jr.; Goorvitch, D.; Abrams, M. C.; Davis, S. P.; Benidar, A.; Farrenq, R.; Guelachvili, G.; Strawa, Anthony W. (Technical Monitor)

    1995-01-01

    Laboratory infrared emission spectra of X 2piOH obtained with the Solar McMath FTS and the U. Paris (Orsay) FTS are used in an inversion procedure to experimentally determine the electric dipole moment function (EDMF) of the hydroxyl radical. The spectra produced at Kitt Peak show vibrational levels up to v = 10 and rotational lines in the range, -25.5 less than or equal to m less than or equal to 12.5. The following vibrational quantum number ranges were observed: for DELTA v = -1, v prime = 1 - 9, for DELTA v = -2, v prime = 2 - 10, and for DELTA v = - 3, v prime = 6 - 10. The spectra produced at Orsay show DELTA v = -1, with v prime = 1 - 4 and -22.5 less than or equal to m less than or equal to 9.5 as well as DELTA v = 0, with v prime= 1 - 3, and 9.5 less than or equal to m less than or equal to 25.5. The OH rovibrational wavefunctions used in the inversion procedure were calculated using a procedure which reproduces observed rotational constants with a high level of accuracy. Comparisons of our EDMF are made with previous experimental and theoretical work.

  6. Functional changes in regulatory T cells during an experimental infection with sparganum (plerocercofid of Spirometra mansoni).

    PubMed

    Kim, Hyung-Ran; Lee, Su-Min; Won, Jong-Wha; Lim, Woosung; Moon, Byung-In; Yang, Hyun-Jong; Seoh, Ju-Young

    2013-01-01

    Regulatory T (Treg) cells are important in the regulation of immune response, but the exact regulation of Treg-cell function in vivo is still not well known. In the present study, we investigated the functional activity of CD4(+) CD25(+) Treg cells as well as the frequency and number of CD4(+) CD25(+) FoxP3(+) Treg cells in the spleens of experimentally infected mice with a tissue-migrating parasite, sparganum (plerocercoid of Spirometra mansoni) for 3 weeks. The results demonstrated fluctuations in the Treg-cell function during the parasite infection, being up-regulated at day 3, down-regulated until day 14, and thereafter up-regulated again at day 21. We also investigated the cytokine-producing capability of the splenocytes to study the pattern of immune response of the mice to the parasite. The results showed decreased capabilities of interleukin-2 (IL-2), interferon-γ (IFN-γ) and IL-17α production, whereas IL-4-producing and IL-10-producing capabilities were increased along with the parasitic infection. Meanwhile, IL-6-producing capability was increased to reach a peak at week 2, and thereafter was decreased to the baseline level. As a regulatory mechanism, we found that Treg-cell function was attenuated in the presence of the crude extracts of sparganum, but was enhanced in the presence of the excretory-secretory products, suggesting that sparganum products were involved in the triggering and regulation of immune response in the acute and chronic phases, respectively. Results show that Treg cells are central in the immune homeostasis in vivo that is maintained by host-parasite interactions during the parasitic infection. PMID:23078673

  7. Tiny giants of gene regulation: experimental strategies for microRNA functional studies.

    PubMed

    Steinkraus, Bruno R; Toegel, Markus; Fulga, Tudor A

    2016-01-01

    The discovery over two decades ago of short regulatory microRNAs (miRNAs) has led to the inception of a vast biomedical research field dedicated to understanding these powerful orchestrators of gene expression. Here we aim to provide a comprehensive overview of the methods and techniques underpinning the experimental pipeline employed for exploratory miRNA studies in animals. Some of the greatest challenges in this field have been uncovering the identity of miRNA-target interactions and deciphering their significance with regard to particular physiological or pathological processes. These endeavors relied almost exclusively on the development of powerful research tools encompassing novel bioinformatics pipelines, high-throughput target identification platforms, and functional target validation methodologies. Thus, in an unparalleled manner, the biomedical technology revolution unceasingly enhanced and refined our ability to dissect miRNA regulatory networks and understand their roles in vivo in the context of cells and organisms. Recurring motifs of target recognition have led to the creation of a large number of multifactorial bioinformatics analysis platforms, which have proved instrumental in guiding experimental miRNA studies. Subsequently, the need for discovery of miRNA-target binding events in vivo drove the emergence of a slew of high-throughput multiplex strategies, which now provide a viable prospect for elucidating genome-wide miRNA-target binding maps in a variety of cell types and tissues. Finally, deciphering the functional relevance of miRNA post-transcriptional gene silencing under physiological conditions, prompted the evolution of a host of technologies enabling systemic manipulation of miRNA homeostasis as well as high-precision interference with their direct, endogenous targets. For further resources related to this article, please visit the WIREs website. PMID:26950183

  8. Tiny giants of gene regulation: experimental strategies for microRNA functional studies

    PubMed Central

    Steinkraus, Bruno R.; Toegel, Markus

    2016-01-01

    The discovery over two decades ago of short regulatory microRNAs (miRNAs) has led to the inception of a vast biomedical research field dedicated to understanding these powerful orchestrators of gene expression. Here we aim to provide a comprehensive overview of the methods and techniques underpinning the experimental pipeline employed for exploratory miRNA studies in animals. Some of the greatest challenges in this field have been uncovering the identity of miRNA–target interactions and deciphering their significance with regard to particular physiological or pathological processes. These endeavors relied almost exclusively on the development of powerful research tools encompassing novel bioinformatics pipelines, high‐throughput target identification platforms, and functional target validation methodologies. Thus, in an unparalleled manner, the biomedical technology revolution unceasingly enhanced and refined our ability to dissect miRNA regulatory networks and understand their roles in vivo in the context of cells and organisms. Recurring motifs of target recognition have led to the creation of a large number of multifactorial bioinformatics analysis platforms, which have proved instrumental in guiding experimental miRNA studies. Subsequently, the need for discovery of miRNA–target binding events in vivo drove the emergence of a slew of high‐throughput multiplex strategies, which now provide a viable prospect for elucidating genome‐wide miRNA–target binding maps in a variety of cell types and tissues. Finally, deciphering the functional relevance of miRNA post‐transcriptional gene silencing under physiological conditions, prompted the evolution of a host of technologies enabling systemic manipulation of miRNA homeostasis as well as high‐precision interference with their direct, endogenous targets. WIREs Dev Biol 2016, 5:311–362. doi: 10.1002/wdev.223 For further resources related to this article, please visit the WIREs website. PMID:26950183

  9. The Head Injury Transportation Straight to Neurosurgery (HITS-NS) randomised trial: a feasibility study.

    PubMed Central

    Lecky, Fiona; Russell, Wanda; Fuller, Gordon; McClelland, Graham; Pennington, Elspeth; Goodacre, Steve; Han, Kyee; Curran, Andrew; Holliman, Damien; Freeman, Jennifer; Chapman, Nathan; Stevenson, Matt; Byers, Sonia; Mason, Suzanne; Potter, Hugh; Coats, Tim; Mackway-Jones, Kevin; Peters, Mary; Shewan, Jane; Strong, Mark

    2016-01-01

    BACKGROUND Reconfiguration of trauma services, with direct transport of traumatic brain injury (TBI) patients to neuroscience centres (NCs), bypassing non-specialist acute hospitals (NSAHs), could potentially improve outcomes. However, delays in stabilisation of airway, breathing and circulation (ABC) and the difficulties in reliably identifying TBI at scene may make this practice deleterious compared with selective secondary transfer from nearest NSAH to NC. National Institute for Health and Care Excellence guidance and systematic reviews suggested equipoise and poor-quality evidence - with regard to 'early neurosurgery' in this cohort - which we sought to address. METHODS Pilot cluster randomised controlled trial of bypass to NC conducted in two ambulance services with the ambulance station (n = 74) as unit of cluster [Lancashire/Cumbria in the North West Ambulance Service (NWAS) and the North East Ambulance Service (NEAS)]. Adult patients with signs of isolated TBI [Glasgow Coma Scale (GCS) score of < 13 in NWAS, GCS score of < 14 in NEAS] and stable ABC, injured nearest to a NSAH were transported either to that hospital (control clusters) or bypassed to the nearest NC (intervention clusters). PRIMARY OUTCOMES recruitment rate, protocol compliance, selection bias as a result of non-compliance, accuracy of paramedic TBI identification (overtriage of study inclusion criteria) and pathway acceptability to patients, families and staff. 'Open-label' secondary outcomes: 30-day mortality, 6-month Extended Glasgow Outcome Scale (GOSE) and European Quality of Life-5 Dimensions. RESULTS Overall, 56 clusters recruited 293 (169 intervention, 124 control) patients in 12 months, demonstrating cluster randomised pre-hospital trials as viable for heath service evaluations. Overall compliance was 62%, but 90% was achieved in the control arm and when face-to-face paramedic training was possible. Non-compliance appeared to be driven by proximity of the nearest hospital

  10. Hand-tool-tissue interaction forces in neurosurgery for haptic rendering.

    PubMed

    Aggravi, Marco; De Momi, Elena; DiMeco, Francesco; Cardinale, Francesco; Casaceli, Giuseppe; Riva, Marco; Ferrigno, Giancarlo; Prattichizzo, Domenico

    2016-08-01

    Haptics provides sensory stimuli that represent the interaction with a virtual or tele-manipulated object, and it is considered a valuable navigation and manipulation tool during tele-operated surgical procedures. Haptic feedback can be provided to the user via cutaneous information and kinesthetic feedback. Sensory subtraction removes the kinesthetic component of the haptic feedback, having only the cutaneous component provided to the user. Such a technique guarantees a stable haptic feedback loop, while it keeps the transparency of the tele-operation system high, which means that the system faithfully replicates and render back the user's directives. This work focuses on checking whether the interaction forces during a bench model neurosurgery operation can lie in the solely cutaneous perception of the human finger pads. If this assumption is found true, it would be possible to exploit sensory subtraction techniques for providing surgeons with feedback from neurosurgery. We measured the forces exerted to surgical tools by three neurosurgeons performing typical actions on a brain phantom, using contact force sensors, while the forces exerted by the tools to the phantom tissue were recorded using a load cell placed under the brain phantom box. The measured surgeon-tool contact forces were 0.01-3.49 N for the thumb and 0.01-6.6 N for index and middle finger, whereas the measured tool-tissue interaction forces were from six to 11 times smaller than the contact forces, i.e., 0.01-0.59 N. The measurements for the contact forces fit the range of the cutaneous sensitivity for the human finger pad; thus, we can say that, in a tele-operated robotic neurosurgery scenario, it would possible to render forces at the fingertip level by conveying haptic cues solely through the cutaneous channel of the surgeon's finger pads. This approach would allow high transparency and high stability of the haptic feedback loop in a tele-operation system. PMID:26718558

  11. German Emergency Care in Neurosurgery and Military Neurology during World War II, 1939-1945.

    PubMed

    Stahnisch, Frank W

    2016-01-01

    A critical analysis of the historical involvement of neurology and neurosurgery in military emergency care services enables us to better contextualize and appreciate the development of modern neurology at large. Wartime neurosurgery and civil brain science during the German Nazi period tightly coalesced in examining the specific injury types, which military neurosurgeons such as Wilhelm Toennis, Klaus Joachim Zuelch, and Georg Merrem encountered and treated based on their neurophysiological understanding gained from earlier peacetime research. Collaborative associations with Dr. Toennis in particular proved to be highly beneficial to other military neurologists and neurosurgeons during World War II and beyond. This article also discusses the prewar developments and considers the fate of German neurosurgeons and military neurologists after the war. The envisaged dynamic concepts of fast action, reaction, and recycling, which contemporary physicians had intensively studied in the preceding scientific experiments in their neurophysiological laboratories, had already been introduced into neurological surgery during the interwar period. In retrospect, World War II emergency rescue units greatly strengthened military operations through an active process of 'recycling' indispensable army personnel. Neurosurgical emergency chains thereby introduced another decisive step in the modernization of warfare, in that they increased the momentum of military mobility in the field. Notwithstanding the violence of warfare and the often inhumane ways in which such knowledge in the field of emergency neurology was gained, the protagonists among the group of experts in military neurology and neurosurgery strongly contributed to the postwar clinical neuroscience community in Germany. In differing political pretexts, this became visible in both East Germany and West Germany after the war, while the specific military and political conditions under which this knowledge of emergency medicine

  12. Experimental triplet and quadruplet fluctuation densities and spatial distribution function integrals for pure liquids

    SciTech Connect

    Ploetz, Elizabeth A.; Karunaweera, Sadish; Smith, Paul E.

    2015-01-28

    Fluctuation solution theory has provided an alternative view of many liquid mixture properties in terms of particle number fluctuations. The particle number fluctuations can also be related to integrals of the corresponding two body distribution functions between molecular pairs in order to provide a more physical picture of solution behavior and molecule affinities. Here, we extend this type of approach to provide expressions for higher order triplet and quadruplet fluctuations, and thereby integrals over the corresponding distribution functions, all of which can be obtained from available experimental thermodynamic data. The fluctuations and integrals are then determined using the International Association for the Properties of Water and Steam Formulation 1995 (IAPWS-95) equation of state for the liquid phase of pure water. The results indicate small, but significant, deviations from a Gaussian distribution for the molecules in this system. The pressure and temperature dependence of the fluctuations and integrals, as well as the limiting behavior as one approaches both the triple point and the critical point, are also examined.

  13. Experimental Removal and Recovery of Subtidal Grazers Highlights the Importance of Functional Redundancy and Temporal Context

    PubMed Central

    Elahi, Robin; Sebens, Kenneth P.

    2013-01-01

    The extent to which different grazers are functionally redundant has strong implications for the maintenance of community structure and function. Grazing by red urchins (Strongylocentrotus franciscanus) on temperate rocky reefs can initiate a switch from invertebrate or macroalgal dominance to an algal crust state, but can also cause increases in the density of molluscan mesograzers. In this study, we tested the hypothesis that red urchins and lined chitons (Tonicella spp.) are redundant in the maintenance of available space, defined as encrusting algae and bare rock. In a factorial field experiment replicated at three sites, we reduced the densities of urchins and chitons on subtidal rock walls for nine months. The effects of grazers were interpreted in the context of natural temporal variation by monitoring the benthic community one year before, during, and after grazer removal. The removal of each grazer in isolation had no effect on the epilithic community, but the removal of both grazers caused an increase in sessile invertebrates. The increase was due primarily to clonal ascidians, which displayed a large (∼75%) relative increase in response to the removal of both grazers. However, the observed non-additive responses to grazer removal were temporary and smaller than seasonal fluctuations. Our data demonstrate that urchins and chitons can be redundant in the maintenance of available space, and highlight the value of drawing conclusions from experimental manipulations within an extended temporal context. PMID:24250819

  14. Ultrafine particles in the airway aggravated experimental lung injury through impairment in Treg function.

    PubMed

    Li, Guanggang; Cao, Yinghua; Sun, Yue; Xu, Ruxiang; Zheng, Zhendong; Song, Haihan

    2016-09-01

    Acute lung injury (ALI) is a life-threatening condition characterized by rapid-onset alveolar-capillary damage mediated by pathogenic proinflammatory immune responses. Since exposure to airway particulate matter (PM) could significantly change the inflammatory status of the individual, we investigated whether PM instillation in the airway could alter the course of ALI, using a murine model with experimental lung injury induced by intratracheal LPS challenge. We found that PM-treated mice presented significantly aggravated lung injury, which was characterized by further reductions in body weight, increased protein concentration in the bronchoalveolar lavage (BAL), and higher mortality rate, compared to control saline-treated mice. The PM-treated mice also presented elevated lung and systemic type 1 T helper cell (Th1) frequency as well as reduced lung regulatory T cell (Treg) frequency, which was associated with severity of lung injury. Further examinations revealed that the Treg function was impaired in PM-treated mice, characterized by significantly repressed transforming growth factor beta production. Adoptive transfer of functional Tregs from control mice to PM-treated mice significantly improved their prognosis after intratracheal LPS challenge. Together, these results demonstrated that first, PM in the airway aggravated lung injury; second, severity of lung injury was associated with T cell subset imbalance in PM-treated mice; and third, PM treatment induced quantitative as well as qualitative changes in the Tregs. PMID:27179778

  15. Experimental triplet and quadruplet fluctuation densities and spatial distribution function integrals for pure liquids.

    PubMed

    Ploetz, Elizabeth A; Karunaweera, Sadish; Smith, Paul E

    2015-01-28

    Fluctuation solution theory has provided an alternative view of many liquid mixture properties in terms of particle number fluctuations. The particle number fluctuations can also be related to integrals of the corresponding two body distribution functions between molecular pairs in order to provide a more physical picture of solution behavior and molecule affinities. Here, we extend this type of approach to provide expressions for higher order triplet and quadruplet fluctuations, and thereby integrals over the corresponding distribution functions, all of which can be obtained from available experimental thermodynamic data. The fluctuations and integrals are then determined using the International Association for the Properties of Water and Steam Formulation 1995 (IAPWS-95) equation of state for the liquid phase of pure water. The results indicate small, but significant, deviations from a Gaussian distribution for the molecules in this system. The pressure and temperature dependence of the fluctuations and integrals, as well as the limiting behavior as one approaches both the triple point and the critical point, are also examined. PMID:25637990

  16. Neural convergence and divergence in the mammalian cerebral cortex: from experimental neuroanatomy to functional neuroimaging

    PubMed Central

    Man, Kingson; Kaplan, Jonas; Damasio, Hanna; Damasio, Antonio

    2013-01-01

    A development essential for understanding the neural basis of complex behavior and cognition is the description, during the last quarter of the twentieth century, of detailed patterns of neuronal circuitry in the mammalian cerebral cortex. This effort established that sensory pathways exhibit successive levels of convergence, from the early sensory cortices to sensory-specific association cortices and to multisensory association cortices, culminating in maximally integrative regions; and that this convergence is reciprocated by successive levels of divergence, from the maximally integrative areas all the way back to the early sensory cortices. This article first provides a brief historical review of these neuroanatomical findings, which were relevant to the study of brain and mind-behavior relationships using a variety of approaches and to the proposal of heuristic anatomo-functional frameworks. In a second part, the article reviews new evidence that has accumulated from studies of functional neuroimaging, employing both univariate and multivariate analyses, as well as electrophysiology, in humans and other mammals, that the integration of information across the auditory, visual, and somatosensory-motor modalities proceeds in a content-rich manner. Behaviorally and cognitively relevant information is extracted from and conserved across the different modalities, both in higher-order association cortices and in early sensory cortices. Such stimulus-specific information is plausibly relayed along the neuroanatomical pathways alluded to above. The evidence reviewed here suggests the need for further in-depth exploration of the intricate connectivity of the mammalian cerebral cortex in experimental neuroanatomical studies. PMID:23840023

  17. Effects of transcutaneous electrical nerve stimulation on quadriceps function in individuals with experimental knee pain.

    PubMed

    Son, S J; Kim, H; Seeley, M K; Feland, J B; Hopkins, J T

    2016-09-01

    Knee joint pain (KJP) is a cardinal symptom in knee pathologies, and quadriceps inhibition is commonly observed among KJP patients. Previously, KJP independently reduced quadriceps strength and activation. However, it remains unknown how disinhibitory transcutaneous electrical nerve stimulation (TENS) will affect inhibited quadriceps motor function. This study aimed at examining changes in quadriceps maximum voluntary contraction (MVC) and central activation ratio (CAR) before and after sensory TENS following experimental knee pain. Thirty healthy participants were assigned to either the TENS or placebo groups. All participants underwent three separate data collection sessions consisting of two saline infusions and one no infusion control in a crossover design. TENS or placebo treatment was administered to each group for 20 min. Quadriceps MVC and CAR were measured at baseline, infusion, treatment, and post-treatment. Perceived knee pain intensity was measured on a 100-mm visual analogue scale. Post-hoc analysis revealed that hypertonic saline infusion significantly reduced the quadriceps MVC and CAR compared with control sessions (P < 0.05). Sensory TENS, however, significantly restored inhibited quadriceps motor function compared with placebo treatment (P < 0.05). There was a negative correlation between changes in MVC and knee pain (r = 0.33, P < 0.001), and CAR and knee pain (r = 0.62, P < 0.001), respectively. PMID:26346597

  18. Experimental triplet and quadruplet fluctuation densities and spatial distribution function integrals for pure liquids

    PubMed Central

    Karunaweera, Sadish

    2015-01-01

    Fluctuation solution theory has provided an alternative view of many liquid mixture properties in terms of particle number fluctuations. The particle number fluctuations can also be related to integrals of the corresponding two body distribution functions between molecular pairs in order to provide a more physical picture of solution behavior and molecule affinities. Here, we extend this type of approach to provide expressions for higher order triplet and quadruplet fluctuations, and thereby integrals over the corresponding distribution functions, all of which can be obtained from available experimental thermodynamic data. The fluctuations and integrals are then determined using the International Association for the Properties of Water and Steam Formulation 1995 (IAPWS-95) equation of state for the liquid phase of pure water. The results indicate small, but significant, deviations from a Gaussian distribution for the molecules in this system. The pressure and temperature dependence of the fluctuations and integrals, as well as the limiting behavior as one approaches both the triple point and the critical point, are also examined. PMID:25637990

  19. Noble gas adsorption in two-dimensional zeolites: a combined experimental and density functional theory study

    NASA Astrophysics Data System (ADS)

    Wang, Mengen; Zhong, Jianqiang; Boscoboinik, Jorge Anibal; Lu, Deyu

    Zeolites are important industrial catalysts with porous three-dimensional structures. The catalytically active sites are located inside the pores, thus rendering them inaccessible for surface science measurements. We synthesized a two-dimensional (2D) zeolite model system, consisting of an (alumino)silicate bilayer weakly bound to a Ru (0001) surface. The 2D zeolite is suitable for surface science studies; it allows a detailed characterization of the atomic structure of the active site and interrogation of the model system during the catalytic reaction. As an initial step, we use Ar adsorption to obtain a better understanding of the atomic structure of the 2D zeolite. In addition, atomic level studies of rare gas adsorption and separation by zeolite are important for its potential application in nuclear waste sequestration. Experimental studies found that Ar atoms can be trapped inside the 2D-zeolite, raising an interesting question on whether Ar atoms are trapped inside the hexagonal prism nano-cages or at the interface between the (alumino)silicate bilayer and Ru(0001), or both. DFT calculations using van der Waals density functionals were carried out to determine the preferred Ar adsorption sites and the corresponding adsorption energies. This research used resources of the Center for Functional Nanomaterials, which is a U.S. DOE Office of Science Facility, at Brookhaven National Laboratory under Contract No. DE-SC0012704.

  20. Computational Modeling for Enhancing Soft Tissue Image Guided Surgery: An Application in Neurosurgery

    PubMed Central

    Miga, Michael I.

    2016-01-01

    With the recent advances in computing, the opportunities to translate computational models to more integrated roles in patient treatment are expanding at an exciting rate. One area of considerable development has been directed towards correcting soft tissue deformation within image guided neurosurgery applications. This review captures the efforts that have been undertaken towards enhancing neuronavigation by the integration of soft tissue biomechanical models, imaging and sensing technologies, and algorithmic developments. In addition, the review speaks to the evolving role of modeling frameworks within surgery and concludes with some future directions beyond neurosurgical applications. PMID:26354118

  1. Principles of Neuro-anesthesia in Neurosurgery for Intensive Care Unit Nurses.

    PubMed

    Feil, Marian; Irick, Nicole A

    2016-03-01

    As neurosurgical interventions and procedures are advancing, so is the specialty of neuro-anesthesia. The neurosurgeon and the neuro-anesthetist are focused on providing each patient with the best possible outcome. Throughout the surgery, the main priorities of the neuro-anesthetist are patient safety, patient well-being, surgical field exposure, and patient positioning. Potential postoperative complications include nausea and vomiting. Postoperative visual loss is a complication of neurosurgery, most specifically spine surgery, whose origins are unknown. Postoperative considerations for the intensive care unit nurse should include receiving a thorough clinical handoff from the anesthesia provider to ensure care continuity and patient safety. PMID:26873761

  2. Effect of melatonin on the functional recovery from experimental traumatic compression of the spinal cord

    PubMed Central

    Schiaveto-de-Souza, A.; da-Silva, C.A.; Defino, H.L.A.; Bel, E.A.Del

    2013-01-01

    Spinal cord injury is an extremely severe condition with no available effective therapies. We examined the effect of melatonin on traumatic compression of the spinal cord. Sixty male adult Wistar rats were divided into three groups: sham-operated animals and animals with 35 and 50% spinal cord compression with a polycarbonate rod spacer. Each group was divided into two subgroups, each receiving an injection of vehicle or melatonin (2.5 mg/kg, intraperitoneal) 5 min prior to and 1, 2, 3, and 4 h after injury. Functional recovery was monitored weekly by the open-field test, the Basso, Beattie and Bresnahan locomotor scale and the inclined plane test. Histological changes of the spinal cord were examined 35 days after injury. Motor scores were progressively lower as spacer size increased according to the motor scale and inclined plane test evaluation at all times of assessment. The results of the two tests were correlated. The open-field test presented similar results with a less pronounced difference between the 35 and 50% compression groups. The injured groups presented functional recovery that was more evident in the first and second weeks. Animals receiving melatonin treatment presented more pronounced functional recovery than vehicle-treated animals as measured by the motor scale or inclined plane. NADPH-d histochemistry revealed integrity of the spinal cord thoracic segment in sham-operated animals and confirmed the severity of the lesion after spinal cord narrowing. The results obtained after experimental compression of the spinal cord support the hypothesis that melatonin may be considered for use in clinical practice because of its protective effect on the secondary wave of neuronal death following the primary wave after spinal cord injury. PMID:23579633

  3. Effects on symptoms and lung function in humans experimentally exposed to diesel exhaust.

    PubMed Central

    Rudell, B; Ledin, M C; Hammarström, U; Stjernberg, N; Lundbäck, B; Sandström, T

    1996-01-01

    OBJECTIVES: Diesel exhaust is a common air pollutant made up of several gases, hydrocarbons, and particles. An experimental study was carried out which was designed to evaluate if a particle trap on the tail pipe of an idling diesel engine would reduce effects on symptoms and lung function caused by the diesel exhaust, compared with exposure to unfiltered exhaust. METHODS: Twelve healthy non-smoking volunteers (aged 20-37) were investigated in an exposure chamber for one hour during light work on a bicycle ergometer at 75 W. Each subject underwent three separate double blind exposures in a randomised sequence: to air and to diesel exhaust with the particle trap at the tail pipe and to unfiltered diesel exhaust. Symptoms were recorded according to the Borg scale before, every 10 minutes during, and 30 minutes after the exposure. Lung function was measured with a computerised whole body plethysmograph. RESULTS: The ceramic wall flow particle trap reduced the number of particles by 46%, whereas other compounds were relatively constant. It was shown that the most prominent symptoms during exposure to diesel exhaust were irritation of the eyes and nose and an unpleasant smell increasing during exposure. Both airway resistance (R(aw)) and specific airway resistance (SR(aw)) increased significantly during the exposures to diesel exhaust. Despite the 46% reduction in particle numbers by the trap effects on symptoms and lung function were not significantly attenuated. CONCLUSION: Exposure to diesel exhaust caused symptoms and bronchoconstriction which were not significantly reduced by a particle trap. PMID:8943829

  4. Nanovector formation by functionalization of TRAIL ligand on single-walled carbon nanotube: Experimental and theoretical evidences

    NASA Astrophysics Data System (ADS)

    Zakaria, Al Batoul; Picaud, Fabien; Duverger, Eric; Devaux, Xavier; Delabrousse, Eric; Gharbi, Tijani; Micheau, Olivier; Herlem, Guillaume

    2015-07-01

    The synthesis and the characterization of a novel nanovector based on oxidized single-walled carbon nanotubes (SWCNT) functionalized with tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) via noncovalent 1-pyrenebutanoic acid N-hydrosuccinimid ester (PSE) is described. Experimental noncovalent functionalized SWCNT by PSE are compared to full DFT theoretical predictions. For this, several experimental techniques are gathered to prove the well functionalization of oxidized SWCNT by π-π stacking such as micro Raman and XPS spectroscopy analysis coupled to full-DFT calculations. Scanning transmission electron microscopy (STEM) coupled to energy dispersive spectroscopy (EDS) underline the presence of TRAIL ligands on the nanovector.

  5. The genesis of neurosurgery and the evolution of the neurosurgical operative environment: part II--concepts for future development, 2003 and beyond.

    PubMed

    Liu, Charles Y; Spicer, Mark; Apuzzo, Michael L J

    2003-01-01

    The future development of the neurosurgical operative environment is driven principally by concurrent development in science and technology. In the new millennium, these developments are taking on a Jules Verne quality, with the ability to construct and manipulate the human organism and its surroundings at the level of atoms and molecules seemingly at hand. Thus, an examination of currents in technology advancement from the neurosurgical perspective can provide insight into the evolution of the neurosurgical operative environment. In the future, the optimal design solution for the operative environment requirements of specialized neurosurgery may take the form of composites of venues that are currently mutually distinct. Advances in microfabrication technology and laser optical manipulators are expanding the scope and role of robotics, with novel opportunities for bionic integration. Assimilation of biosensor technology into the operative environment promises to provide neurosurgeons of the future with a vastly expanded set of physiological data, which will require concurrent simplification and optimization of analysis and presentation schemes to facilitate practical usefulness. Nanotechnology derivatives are shattering the maximum limits of resolution and magnification allowed by conventional microscopes. Furthermore, quantum computing and molecular electronics promise to greatly enhance computational power, allowing the emerging reality of simulation and virtual neurosurgery for rehearsal and training purposes. Progressive minimalism is evident throughout, leading ultimately to a paradigm shift as the nanoscale is approached. At the interface between the old and new technological paradigms, issues related to integration may dictate the ultimate emergence of the products of the new paradigm. Once initiated, however, history suggests that the process of change will proceed rapidly and dramatically, with the ultimate neurosurgical operative environment of the future

  6. Intrinsic functional connectivity of insular cortex and symptoms of sickness during acute experimental inflammation.

    PubMed

    Lekander, Mats; Karshikoff, Bianka; Johansson, Emilia; Soop, Anne; Fransson, Peter; Lundström, Johan N; Andreasson, Anna; Ingvar, Martin; Petrovic, Predrag; Axelsson, John; Nilsonne, Gustav

    2016-08-01

    Task-based fMRI has been used to study the effects of experimental inflammation on the human brain, but it remains unknown whether intrinsic connectivity in the brain at rest changes during a sickness response. Here, we investigated the effect of experimental inflammation on connectivity between areas relevant for monitoring of bodily states, motivation, and subjective symptoms of sickness. In a double-blind randomized controlled experiment, 52 healthy volunteers were injected with 0.6ng/kg LPS (lipopolysaccharide) or placebo, and participated in a resting state fMRI experiment after approximately 2h 45min. Resting state fMRI data were available from 48 participants, of which 28 received LPS and 20 received placebo. Bilateral anterior and bilateral posterior insula sections were used as seed regions and connectivity with bilateral orbitofrontal and cingulate (anterior and middle) cortices was investigated. Back pain, headache and global sickness increased significantly after as compared to before LPS, while a non-significant trend was shown for increased nausea. Compared to placebo, LPS was followed by increased connectivity between left anterior insula and left midcingulate cortex. This connectivity was significantly correlated to increase in back pain after LPS and tended to be related to increased global sickness, but was not related to increased headache or nausea. LPS did not affect the connectivity from other insular seeds. In conclusion, the finding of increased functional connectivity between left anterior insula and middle cingulate cortex suggests a potential neurophysiological mechanism that can be further tested to understand the subjective feeling of malaise and discomfort during a sickness response. PMID:26732827

  7. Experimental determination of the 1 Sigma(+) state electric dipole moment function of carbon monoxide up to a large internuclear separation

    NASA Technical Reports Server (NTRS)

    Chackerian, C., Jr.; Farrenq, R.; Guelachvili, G.; Rossetti, C.; Urban, W.

    1984-01-01

    Experimental intensity information is combined with numerically obtained vibrational wave functions in a nonlinear least-squares fitting procedure to obtain the ground electronic state electric dipole moment function of carbon monoxide valid in the range of nuclear oscillation (0.87-1.91 A) of about the V = 38th vibrational level. Vibrational transition matrix elements are computed from this function for Delta V = 1, 2, 3 with V not more than 38.

  8. Three-dimensional multimodal image-guidance for neurosurgery

    SciTech Connect

    Peters, T.; Munger, P.; Comeau, R.; Evans, A.; Olivier, A.; Davey, B.

    1996-04-01

    The authors address the use of multimodality imaging as an aid to the planning and guidance of neurosurgical procedures, and discuss the integration of anatomical (CT and MRI), vascular (DSA), and functional (PET) data for presentation to the surgeon during surgery. The workstation is an enhancement of a commercially available system, and in addition to the guidance offered via a hand-held probe, it incorporates the use of multimodality imaging and adds enhanced realism to the surgeon through the use of a stereoscopic three-dimensional (3-D) image display. The probe may be visualized stereoscopically in single or multimodality images. The integration of multimodality data in this manner provides the surgeon with a complete overview of brain structures on which he is performing surgery, or through which he is passing probes or cannulas, enabling him to avoid critical vessels and/or structures of functional significance.

  9. Understanding Brain, Mind and Soul: Contributions from Neurology and Neurosurgery

    PubMed Central

    Pandya, Sunil K.

    2011-01-01

    Treatment of diseases of the brain by drugs or surgery necessitates an understanding of its structure and functions. The philosophical neurosurgeon soon encounters difficulties when localising the abstract concepts of mind and soul within the tangible 1300-gram organ containing 100 billion neurones. Hippocrates had focused attention on the brain as the seat of the mind. The tabula rasa postulated by Aristotle cannot be localised to a particular part of the brain with the confidence that we can localise spoken speech to Broca’s area or the movement of limbs to the contralateral motor cortex. Galen’s localisation of imagination, reasoning, judgement and memory in the cerebral ventricles collapsed once it was evident that the functional units–neurones–lay in the parenchyma of the brain. Experiences gained from accidental injuries (Phineas Gage) or temporal lobe resection (William Beecher Scoville); studies on how we see and hear and more recent data from functional magnetic resonance studies have made us aware of the extensive network of neurones in the cerebral hemispheres that subserve the functions of the mind. The soul or atman, credited with the ability to enliven the body, was located by ancient anatomists and philosophers in the lungs or heart, in the pineal gland (Descartes), and generally in the brain. When the deeper parts of the brain came within the reach of neurosurgeons, the brainstem proved exceptionally delicate and vulnerable. The concept of brain death after irreversible damage to it has made all of us aware of ‘the cocktail of brain soup and spark’ in the brainstem so necessary for life. If there be a soul in each of us, surely, it is enshrined here. PMID:21694966

  10. Effect of Angiotensin(1-7) on Heart Function in an Experimental Rat Model of Obesity

    PubMed Central

    Blanke, Katja; Schlegel, Franziska; Raasch, Walter; Bader, Michael; Dähnert, Ingo; Dhein, Stefan; Salameh, Aida

    2015-01-01

    Aim: Obesity is a risk factor for the development of cardiovascular diseases. Recently it was shown that overexpression of the Mas-receptor antagonist angiotensin(1-7) could prevent from diet-induced obesity. However, it remained unclear whether diet-induced obesity and angiotensin(1-7) overexpression might also have effects on the cardiovascular system in these rats. Methods:Twenty three male Sprague Dawley rats were fed with standard chow (SD+chow, n = 5) or a cafeteria diet (SD+CD, n = 6) for 5 months. To investigate the effect of angiotensin(1-7) transgenic rats, expressing an angiotensin(1-7)-producing fusion protein in testis were used. These transgenic rats also received a 5 month's feeding period with either chow (TGR+chow, n = 6) or cafeteria diet (TGR+CD, n = 6), respectively. Hemodynamic measurements (pressure-volume loops) were carried out to assess cardiac function and blood pressure. Subsequently, hearts were explanted and investigated according to the Langendorff technique. Furthermore, cardiac remodeling in these animals was investigated histologically. Results:After 5 months cafeteria diet feeding rats showed a significantly increased body weight, which could be prevented in transgenic rats. However, there was no effect on cardiac performance after cafeteria diet in non-transgenic and transgenic rats. Moreover, overexpression of angiotensin(1-7) deteriorated cardiac contractility as indicated by impaired dp/dt. Furthermore, histological analysis revealed that cafeteria diet led to myocardial fibrosis in both, control and transgenic rats and this was not inhibited by an overproduction of angiotensin(1-7). Conclusion:These results indicate that an overexpression of circulating angiotensin(1-7) prevents a cafeteria diet-induced increase in body weight, but does not affect cardiac performance in this experimental rat model of obesity. Furthermore, overexpression of angiotensin(1-7) alone resulted in an impairment of cardiac function. PMID:26733884

  11. Anti-Thymocyte Globulin Induces Neoangiogenesis and Preserves Cardiac Function after Experimental Myocardial Infarction

    PubMed Central

    Lichtenauer, Michael; Mildner, Michael; Werba, Gregor; Beer, Lucian; Hoetzenecker, Konrad; Baumgartner, Andrea; Hasun, Matthias; Nickl, Stefanie; Mitterbauer, Andreas; Zimmermann, Matthias; Gyöngyösi, Mariann; Podesser, Bruno Karl; Klepetko, Walter; Ankersmit, Hendrik Jan

    2012-01-01

    Rationale Acute myocardial infarction (AMI) followed by ventricular remodeling is the major cause of congestive heart failure and death in western world countries. Objective Of relevance are reports showing that infusion of apoptotic leucocytes or anti-lymphocyte serum after AMI reduces myocardial necrosis and preserves cardiac function. In order to corroborate this therapeutic mechanism, the utilization of an immunosuppressive agent with a comparable mechanism, such as anti-thymocyte globulin (ATG) was evaluated in this study. Methods and Results AMI was induced in rats by ligation of the left anterior descending artery. Initially after the onset of ischemia, rabbit ATG (10 mg/rat) was injected intravenously. In vitro and in vivo experiments showed that ATG induced a pronounced release of pro-angiogenic and chemotactic factors. Moreover, paracrine factors released from ATG co-incubated cell cultures conferred a down-regulation of p53 in cardiac myocytes. Rats that were injected with ATG evidenced higher numbers of CD68+ macrophages in the ischemic myocardium. Animals injected with ATG evidenced less myocardial necrosis, showed a significant reduction of infarct dimension and an improvement of post-AMI remodeling after six weeks (infarct dimension 24.9% vs. 11.4%, p<0.01). Moreover, a higher vessel density in the peri-infarct region indicated a better collateralization in rats that were injected with ATG. Conclusions These data indicate that ATG, a therapeutic agent successfully applied in clinical transplant immunology, triggered cardioprotective effects after AMI that salvaged ischemic myocardium by down-regulation of p53. This might have raised the resistance against apoptotic cell death during ischemia. The combination of these mechanisms seems to be causative for improved cardiac function and less ventricular remodeling after experimental AMI. PMID:23284885

  12. Functional and Histological Assessment of an Experimental Model of Takotsubo's Cardiomyopathy

    PubMed Central

    Sachdeva, Jaspreet; Dai, Wangde; Kloner, Robert A.

    2014-01-01

    Background Our objectives were to characterize functional and structural features of an experimental model of Takotsubo cardiomyopathy, and its response to beta‐blockers. Methods and Results In protocol 1, a dose‐finding study: 69 rats received various doses of isoproterenol (ISO) and echocardiographic and histologic parameters were measured on days 2 to 3 or day 8. There were no dose‐dependent effects and, out of 69 ISO‐treated rats, 40 (58.0%) survived and 29 (42.0%) died within 24 hours. Of survivors, 30 had apical akinesis averaging 12.1±1.6% of the long axis LV circumference. Out of the 40 survivors, 32.5% showed apical akinesis ≥10%, 42.5% showed akinesis<10% and 25% showed no apical akinesis. The basal portion of the LV was always preserved. At 24 hours, histology and ultrastructure showed necrosis, vacuolization, lipid droplets, mononuclear cell infiltration, damaged mitochondria, and edema. On day 8, apical akinesis fully resolved but histologic abnormalities were still present. In protocol 2, rats were randomized to Control; ISO100 mg/kg; propranolol+ISO; and metoprolol+ISO groups. Pretreatment with propranolol and metoprolol improved survival to 90% and 100% respectively, compared with 60% in the ISO group, but did not reduce the incidence and extent of akinesis or the structural damage. Conclusion TC can be mimicked in a rat model of ISO exposure that demonstrates apical akinesis on days 2 to 3 with full recovery of systolic regional wall motion abnormality despite the presence of persistent foci of necrosis and fibrosis on day 8. Pretreatment with beta‐blockers improved survival but did not affect structural and functional alterations. PMID:24958782

  13. Great hospitals of Asia: the Department of Neurosurgery at Seoul National University College of Medicine.

    PubMed

    Kim, Dong Gyu; Park, Chul-Kee; Paek, Sun Ha; Kim, Jeong Eun; Kim, Chi Heon; Phi, Ji Hoon

    2011-01-01

    Established in 1957, the Department of Neurosurgery at Seoul National University College of Medicine is the one of the oldest neurosurgical departments in Korea. The seven past Chairmen (Bo Sung Sim, Kil Soo Choi, Dae Hee Han, Byung-Kyu Cho, Hyun Jib Kim, Hee-Won Jung, and Dong Gyu Kim) have devoted themselves to the development of the department. The current chair, Chun Kee Chung, assumed the position in July 2010. The current department comprises several clinical programs that encompass the entire spectrum of neurosurgical disorders, with 29 specialized faculty members and care teams in three hospitals: Seoul National University Hospital (SNUH), Boramae Medical Center (BMC), and Seoul National University Bundang Hospital (SNUBH). The remarkable growth of the department during the last half century made it possible to perform 5,666 operations (3,299 at SNUH, 411 at BMC and 1,860 at SNUBH) during 2009. A total of 1,201 articles authored by faculty members were published in scientific journals between 1958 and 2009, approximately 32% of which were published in international journals. The department is regarded as the "Mecca" of neurosurgery in Korea because of its outstanding achievement and the many distinguished alumni with leadership roles in the academic field. This article traces the clinical, academic, and scientific development of the department, its present activities, and its future direction. PMID:21600472

  14. The beginnings of neurosurgery in California during the pre-Cushing era: 1850-1900.

    PubMed

    Keller, T M

    1998-11-01

    The end of the present millennium marks the centennial of Harvey Cushing's European study year, after the completion of his surgical residency under William Stewart Halsted at the Johns Hopkins Hospital and just before beginning his surgical practice in Baltimore, Maryland. The year 2000 marks the sesquicentennial of California's admission to the Union as the 31st state. This report documents a number of the events and achievements that occurred during this "pre-Cushing era" (1850-1900) that contributed to the ultimate development of neurological surgery in California. The historical milestones of the California gold rush, the completion of the Transcontinental Railroad across the Sierra Nevada Mountains, and the careers of early California physicians and educators, including those of Hugh Toland and Levi Cooper Lane, were instrumental in building a foundation for the modern discipline of neurosurgery in the Golden State. This foundation would serve as a cornerstone for surgeons trained by Harvey Cushing (including Howard Naffziger, Carl Rand, and Edward Towne) who would arrive in California early in the 20th century and would define the specialty of neurosurgery. The legacy left by these physicians enhances the celebration of the closure of the millennium. PMID:9802863

  15. Quantifying cortical surface harmonic deformation with stereovision during open cranial neurosurgery

    NASA Astrophysics Data System (ADS)

    Ji, Songbai; Fan, Xiaoyao; Roberts, David W.; Paulsen, Keith D.

    2012-02-01

    Cortical surface harmonic motion during open cranial neurosurgery is well observed in image-guided neurosurgery. Recently, we quantified cortical surface deformation noninvasively with synchronized blood pressure pulsation (BPP) from a sequence of stereo image pairs using optical flow motion tracking. With three subjects, we found the average cortical surface displacement can reach more than 1 mm and in-plane principal strains of up to 7% relative to the first image pair. In addition, the temporal changes in deformation and strain were in concert with BPP and patient respiration [1]. However, because deformation was essentially computed relative to an arbitrary reference, comparing cortical surface deformation at different times was not possible. In this study, we extend the technique developed earlier by establishing a more reliable reference profile of the cortical surface for each sequence of stereo image acquisitions. Specifically, fast Fourier transform (FFT) was applied to the dynamic cortical surface deformation, and the fundamental frequencies corresponding to patient respiration and BPP were identified, which were used to determine the number of image acquisitions for use in averaging cortical surface images. This technique is important because it potentially allows in vivo characterization of soft tissue biomechanical properties using intraoperative stereovision and motion tracking.

  16. da Vinci robot-assisted keyhole neurosurgery: a cadaver study on feasibility and safety.

    PubMed

    Marcus, Hani J; Hughes-Hallett, Archie; Cundy, Thomas P; Yang, Guang-Zhong; Darzi, Ara; Nandi, Dipankar

    2015-04-01

    The goal of this cadaver study was to evaluate the feasibility and safety of da Vinci robot-assisted keyhole neurosurgery. Several keyhole craniotomies were fashioned including supraorbital subfrontal, retrosigmoid and supracerebellar infratentorial. In each case, a simple durotomy was performed, and the flap was retracted. The da Vinci surgical system was then used to perform arachnoid dissection towards the deep-seated intracranial cisterns. It was not possible to simultaneously pass the 12-mm endoscope and instruments through the keyhole craniotomy in any of the approaches performed, limiting visualization. The articulated instruments provided greater dexterity than existing tools, but the instrument arms could not be placed in parallel through the keyhole craniotomy and, therefore, could not be advanced to the deep cisterns without significant clashing. The da Vinci console offered considerable ergonomic advantages over the existing operating room arrangement, allowing the operating surgeon to remain non-sterile and seated comfortably throughout the procedure. However, the lack of haptic feedback was a notable limitation. In conclusion, while robotic platforms have the potential to greatly enhance the performance of transcranial approaches, there is strong justification for research into next-generation robots, better suited to keyhole neurosurgery. PMID:25516094

  17. Perceptions of neurosurgery: a survey of medical students and foundation doctors.

    PubMed

    Hill, Ciaran Scott; Dias, Lalani; Kitchen, Neil

    2011-04-01

    The ratio of applications per place for the British neurosurgical training programme (ST1 level) is currently significantly less than in many other specialities including competitive surgical and radiological programmes. A survey of medical students and junior doctors prior to speciality selection was conducted to assess their perceptions of neurosurgery as a speciality and identify factors that affect career choice and recruitment. A three domain, 17-item questionnaire with a Likert 5-point scale was produced. Two hundred individual paper questionnaires were randomly distributed across a central London teaching trust. Response rate in both groups was 100% with no exclusions. Data were collected by one group and analysed independently with descriptive methods and independent t-tests to determine statistically significant intra-group variability. Results showed marked differences in opinions at the two stages of medical progression and identified several consistencies. Examples include a tendency to rule out neurosurgical careers on the basis of experience with other surgical specialities and fear of inadequate dexterity or intelligence. The results showed variable persistence of traditional stereotypes including a common view that it is a highly competitive male dominated profession although this view significantly diminished with experience. Neurosurgery is an expanding profession at the cutting edge of technology. This study offers an important and interesting insight into why it is not more popular and what can be done to attract the best candidates. PMID:21158517

  18. Sir Victor Horsley (1857-1916) and the birth of English neurosurgery.

    PubMed

    Hughes, J

    2007-02-01

    Modern surgery developed in the second half of the 19th century, at the end of which neurosurgery was established as a profitable region of operative intervention. In the British Isles, the first exponent was Sir William Macewen (1848-1924) in Glasgow. But neuroscience had advanced in London due to the excellence of the neurologists in the several hospitals there. Foremost among English neurosurgeons was Victor Horsley whose career had a worldwide influence on the speciality. Initially, operations were carried out for cranial trauma, the removal of displaced bone or blood clot, and the drainage of abscesses arising from infection of the middle ears and air sinuses. The diagnosis of brain and spinal tumours by neurologists encouraged removal by surgeons, of which Horsley was among the earliest. Horsley performed many operations on animals, experiments opposed by the anti-vivisectionists whose campaigns Horsley countered. Horsley had many other interests, some of which displeased the establishment, and in World War I his experience in neurosurgery was not used. He served as a general surgeon, visiting Egypt, India and Mesopotamia where, in Amara, he died from hyperpyrexia complicating bacillary dysentery. PMID:17356729

  19. Current state-of-the-art and future perspectives of robotic technology in neurosurgery.

    PubMed

    Mattei, Tobias A; Rodriguez, Abraham Hafiz; Sambhara, Deepak; Mendel, Ehud

    2014-07-01

    Neurosurgery is one of the most demanding surgical specialties in terms of precision requirements and surgical field limitations. Recent advancements in robotic technology have generated the possibility of incorporating advanced technological tools to the neurosurgical operating room. Although previous studies have addressed the specific details of new robotic systems, there is very little literature on the strengths and drawbacks of past attempts, currently available platforms and prototypes in development. In this review, the authors present a critical historical analysis of the development of robotic technology in neurosurgery as well as a comprehensive summary of the currently available systems that can be expected to be incorporated to the neurosurgical armamentarium in the near future. Finally, the authors present a critical analysis of the main technical challenges in robotic technology development at the present time (such as the design of improved systems for haptic feedback and the necessity of incorporating intraoperative imaging data) as well as the benefits which robotic technology is expected to bring to specific neurosurgical subspecialties in the near future. PMID:24729137

  20. From the Idea to Its Realization: The Evolution of Minimally Invasive Techniques in Neurosurgery

    PubMed Central

    Grunert, P.

    2013-01-01

    Minimally invasive techniques in neurosurgery evolved in two steps. Many minimally invasive concepts like neuronavigation, endoscopy, or frame based stereotaxy were developed by the pioneers of neurosurgery, but it took decades till further technical developments made the realization and broad clinical application of these early ideas safe and possible. This thesis will be demonstrated by giving examples of the evolution of four minimally invasive techiques: neuronavigation, transsphenoidal pituitary surgery, neuroendoscopy and stereotaxy. The reasons for their early failure and also the crucial steps for the rediscovery of these minimally invasive techniques will be analysed. In the 80th of the 20th century endoscopy became increasingly applied in different surgical fields. The abdominal surgeons coined as first for their endoscopic procedures the term minimally invasive surgery in contrast to open surgery. In neurrosurgery the term minimally invasive surgery stood not in opposiotion to open procedures but was understood as a general concept and philosophy using the modern technology such as neuronavigation, endoscopy and planing computer workstations with the aim to make the procedures less traumatic. PMID:24455231

  1. Experimental Modification of Rat Pituitary Prolactin Cell Function During and After Spaceflight

    NASA Technical Reports Server (NTRS)

    Hymer, W. C.; Salada, T.; Avery, L.; Grindeland, R. E.

    1996-01-01

    Experimental modification of rat pituitary prolactin cell function during and after spaceflight. This study was done to evaluate the effects of microgravity on prolactin (PRL) cells of the male rat pituitary gland. We used the identical passive closed-vial cell culture system that was described for the culture of growth hormone cells (W C. Hymer, R. E. Grindeland, T. Salada, P. Nye, E. Grossman, and R Lane). After an 8-day spaceflight, all flight media (containing released PRL), as well as extracts (containing intracellular PRL), contained significantly lower amounts of immunoreactive PRL than their corresponding ground control samples. On the other hand, these same samples, when assessed for their biological activities by two different in vitro lymphocyte assays, yielded disparate results that may reflect posttranslational modifications to the hormone molecule. Other data showed that: (1) the apparent molecular weights of released PRL molecules were not altered by microgravity; but (2) the region from which the PRL cells came (dorsal or ventral) made a significant difference in the amount and activity of PRL released from the flight cells. Because there is much current interest in the role that PRL may play in the regulation of the immune system and because changes in both cellular and humoral immunity accompany spaceflight, this study could help define future microgravity research in this area.

  2. Quality control and assurance in functional near infrared spectroscopy (fNIRS) experimentation

    NASA Astrophysics Data System (ADS)

    Orihuela-Espina, F.; Leff, D. R.; James, D. R. C.; Darzi, A. W.; Yang, G. Z.

    2010-07-01

    Functional near infrared spectroscopy (fNIRS) is a rapidly developing neuroimaging modality for exploring cortical brain behaviour. Despite recent advances, the quality of fNIRS experimentation may be compromised in several ways: firstly, by altering the optical properties of the tissues encountered in the path of light; secondly, through adulteration of the recovered biological signals (noise) and finally, by modulating neural activity. Currently, there is no systematic way to guide the researcher regarding these factors when planning fNIRS studies. Conclusions extracted from fNIRS data will only be robust if appropriate methodology and analysis in accordance with the research question under investigation are employed. In order to address these issues and facilitate the quality control process, a taxonomy of factors influencing fNIRS data have been established. For each factor, a detailed description is provided and previous solutions are reviewed. Finally, a series of evidence-based recommendations are made with the aim of improving consistency and quality of fNIRS research.

  3. Laryngeal Adductor Function in Experimental Models of Recurrent Laryngeal Nerve Injury

    PubMed Central

    Paniello, Randal C.; Rich, Jason T.; Debnath, Nick L.

    2014-01-01

    Objectives/Hypothesis Most patients with unilateral vocal fold paralysis experience some degree of spontaneous reinnervation, which depends upon the type and severity of recurrent laryngeal nerve (RLN) injury. After partial recovery, the paretic vocal fold may or may not adduct adequately to allow glottic closure, which in turn affects phonatory and swallowing outcomes. This process was studied in a series of canine laryngeal nerve injury models. Study Design Animal (canine) experiments. Methods Maximum stimulable laryngeal adductor pressure (LAP) was measured pre-treatment (baseline) and at 6 months following experimental RLN injuries (total n=59). The 9 study groups were designed to simulate a range of severities of RLN injury. Results The greatest LAP recovery, at 108% of original baseline, was seen in a 50% transection model; the least recovery was seen when the RLN underwent complete transection with repair, at 56% with precise alignment and 50% with alignment reversed. Intermediate models (partial RLN injuries) gave intermediate results. Crush models recovered 105% of LAP, while a half-transection, half-crush injury recovered 72% and cautery injuries recovered 61%. Controls (complete transection without repair) had no measurable recovery. Conclusions The injured RLN has a strong tendency to recover. Restoration of adductor strength, as determined by the LAP, was predictably related to the severity of RLN injury. The model RLN injuries studied provide a range of expected outcomes that can be used for future experiments exploring interventions that may improve post-injury adductor function. PMID:25283381

  4. Experimental measurements of frequency transfer function due to smoothing by spectral dispersion

    NASA Astrophysics Data System (ADS)

    Luce, Jacques; Penninckx, Denis

    2013-02-01

    In order to avoid propagation nonlinearities (Kerr effect, Raman and Brillouin scattering) and optical damage, nanosecond high power lasers such as the Laser MegaJoule (LMJ) amplify quasi-monochromatic pulses. But they generate a static speckle pattern in the focal spot. This speckle pattern needs to be smoothed in order to lower high intensity peaks which are detrimental during the propagation and the interaction with the plasma in the target. Different techniques are implemented to smooth the intensity nevertheless all high power lasers carry at least smoothing by spectral dispersion. It consists in broadening the spectrum through a phase modulator and focusing the different wavelengths at slightly different positions using a diffractive element such as a grating. In the temporal domain, it has been theoretically shown that the pulse power is thus filtered between near field and far field [1, 2]. The filtering allows techniques such as "picket fence" to increase conversion efficiency [1] and reduces detrimental effects of unwanted intensity distortions called FM-AM conversion [2, 3]. Here, to the best of our knowledge we show the first experimental measurement of the frequency transfer function of this filtering. Measurements are in perfect agreement with the numerical calculations.

  5. Effect of vitamin C on endothelial function of children with chronic renal failure: An experimental study

    PubMed Central

    Sabri, Mohammad Reza; Tavana, Esfandiar Najafi; Ahmadi, Alireza; Gheissari, Alaleh

    2015-01-01

    Background: It is well established that improvement of endothelial dysfunction (ED) could prevent or delay the occurrence of cardiovascular disease (CVD) and its related morbidity and mortality in patients with chronic kidney disease (CKD). In this study we investigated whether administration of vitamin C could be effective by improving brachial artery flow-mediated dilation (FMD) and intima media thickness (IMT), two surrogate markers of ED, in children with CKD or chronic renal failure (CRF). Materials and Methods: In this analytic-experimental study children aged 3-18 years with a diagnosis of CRF and a group of healthy children were enrolled. Vitamin C (250 mg/day) administrated for the two studied groups for 1 month. Endothelial function was evaluated by FMD and IMT measurement using vascular Doppler ultrasonography, before and after trial. Results: In this study 18 patients with CRF and 19 normal children as the control group were studied. At baseline mean of IMT and FMD was not different in the two studied groups (P > 0.05). After vitamin C administration IMT decreased significantly in the two studied groups (P < 0.05). FMD increased in the two studied groups but the difference was significant in the control group (P < 0.05). Conclusion: The findings of this interventional trial have demonstrated that vitamin C could have protective effect on ED of patients with CRF possibly in those with severe form of the disease but for obtaining more conclusive results larger sample size is needed. PMID:26918242

  6. Effects of Physical Activity on Children’s Executive Function: Contributions of Experimental Research on Aerobic Exercise

    PubMed Central

    Best, John R.

    2011-01-01

    Executive function refers to the cognitive processes necessary for goal-directed cognition and behavior, which develop across childhood and adolescence. Recent experimental research indicates that both acute and chronic aerobic exercise promote children’s executive function. Furthermore, there is tentative evidence that not all forms of aerobic exercise benefit executive function equally: Cognitively-engaging exercise appears to have a stronger effect than non-engaging exercise on children’s executive function. This review discusses this evidence as well as the mechanisms that may underlie the association between exercise and executive function. Research from a variety of disciplines is covered, including developmental psychology, kinesiology, cognitive neuroscience, and biopsychology. Finally, these experimental findings are placed within the larger context of known links between action and cognition in infancy and early childhood, and the clinical and practical implications of this research are discussed. PMID:21818169

  7. George Gershwin -- a case of new ways in neurosurgery as well as in the history of Western music.

    PubMed

    Gasenzer, Elena; Neugebauer, Edmund A M

    2014-06-01

    George Gershwin, the famous American composer, died in 1937 of a temporal lobe glioma. An emergency surgery was performed by R. Nafziger and W. E. Dandy. The case of George Gershwin indicates the beginning of a new era in music history as well as in the history of neurosurgery. PMID:24633986

  8. Response of vegetation structure and function to experimental drought and flooding in an Alaskan fen

    NASA Astrophysics Data System (ADS)

    Churchill, A. C.; Hollingworth, T. N.; McGuire, A. D.; Turetsky, M. R.

    2010-12-01

    Northern peatlands historically represent a net sink for atmospheric CO2, but the future of peatland carbon balance will be highly dependent upon localized responses to changing climate and disturbance regimes. Remote sensing in interior Alaska has shown a long-term drying trend (i.e., past 50 years) in major wetland complexes, likely in response to warming and increased evapotranspiration. More recently interior Alaska experienced extreme flood and drought events in 2008 (100 yr flood) and 2009 (drought yr). Because peatland vegetation structure and physiology are strongly mediated by the position of the water table, inter-annual variation in hydrology and affiliated environmental conditions such as active layer depth and soil moisture will influence plant CO2 uptake and the overall ecosystem carbon balance. Additionally, hydrology and vegetation responses to directional climate change will influence local carbon cycling rates via altering litter quality and decomposition. At the Alaskan Peatland Experiment (http://www.uoguelph.ca/Apex), located near the Bonanza Creek Experimental Forest, we initiated a water table manipulation during the spring of 2005. Here, our objectives are to quantify the influence of experimental drought and flooding, as well as inter-annual variation in water table position, on plant community composition and CO2 uptake for the growing seasons in 2007-2010. Previous results showed no differences in vegetation structure after two years of water table manipulation; however, after four years we found that the lowered water table treatment (drought) had more deciduous shrubs and fewer mosses than the control treatment. Within the raised water table treatment (flooding), graminoids increased in abundance relative to the control. Rates of Gross Primary Productivity (GPP), measured biweekly during the growing season using static chambers, varied significantly among water table treatments, with the lowest GPP in the drought plot and the highest

  9. Toxoplasma gondii: Effects of diphenyl diselenide in experimental toxoplasmosis on biomarkers of cardiac function.

    PubMed

    Machado, Vanessa S; Bottari, Nathieli B; Baldissera, Matheus D; Isabel de Azevedo, Maria; Rech, Virginia C; Ianiski, Francine R; Vaucher, Rodrigo A; Mendes, Ricardo E; Camillo, Giovana; Vogel, Fernanda F; de la Rue, Mario L; Carmo, Guilherme M; Tonin, Alexandre A; Da Silva, Aleksandro S

    2016-08-01

    This study aimed to investigate the effects of diphenyl diselenide (PhSe)2 to treat mice experimentally infected by Toxoplasma gondii on seric biomarkers of cardiac function (creatine kinase, creatine kinase MB, troponin, and myoglobin), and lactate dehydrogenase, as well as to evaluate the enzymatic activity of creatine kinase (CK) and adenylate kinase (AK) in heart tissue. For the study, 40 female mice were divided into four groups of 10 animals each: the group A (uninfected and untreated), the group B (uninfected and treated), the group C (infected and untreated) and the group D (infected and treated). The inoculation was performed with 50 cysts of T. gondii (ME-49 strain). Mice from groups B and D were treated at days 1 and 20 post-infection (PI) with 5 μmol kg(-1) of (PhSe)2 subcutaneously. On day 30 PI, the mice were anesthetized and euthanized for blood and heart collection. As a result, it was observed a decrease in AK activity (P < 0.01) in the heart samples of groups C and D compared to the group A. Cardiac CK increased in the group C compared to the group A (P < 0.01). CK levels increased in infected mice (the group C) compared to other groups (A and D). Regarding CK-MB level, there was a decrease in the group D compared to the group B, without statistical difference compared to control groups (A and C). It was observed an increase on myoglobin in groups C and D, differently of troponin, which did not show statistical difference (P < 0.05) between groups. Mice from the group C showed an increase in lactate dehydrogenase (LDH) levels compared to other groups (A, B, and D). Histopathological evaluation of heart samples revealed necrosis, hemorrhagic regions and inflammatory infiltrates in mice from the Group C, differently from the group D where animals showed only inflammatory infiltrates. Based on these results we conclude that the (PhSe)2 had a protective effect on the heart in experimental toxoplasmosis by modulating tissue and seric CK

  10. Functional and Pathogenic Differences of Th1 and Th17 Cells in Experimental Autoimmune Encephalomyelitis

    PubMed Central

    Domingues, Helena S.; Mues, Marsilius; Lassmann, Hans; Wekerle, Hartmut; Krishnamoorthy, Gurumoorthy

    2010-01-01

    Background There is consensus that experimental autoimmune encephalomyelitis (EAE) can be mediated by myelin specific T cells of Th1 as well as of Th17 phenotype, but the contribution of either subset to the pathogenic process has remained controversial. In this report, we compare functional differences and pathogenic potential of “monoclonal” T cell lines that recognize myelin oligodendrocyte glycoprotein (MOG) with the same transgenic TCR but are distinguished by an IFN-γ producing Th1-like and IL-17 producing Th17-like cytokine signature. Methods and Findings CD4+ T cell lines were derived from the transgenic mouse strain 2D2, which expresses a TCR recognizing MOG peptide 35–55 in the context of I-Ab. Adoptive transfer of Th1 cells into lymphopenic (Rag2−/−) recipients, predominantly induced “classic” paralytic EAE, whereas Th17 cells mediated “atypical” ataxic EAE in approximately 50% of the recipient animals. Combination of Th1 and Th17 cells potentiated the encephalitogenicity inducing classical EAE exclusively. Th1 and Th17 mediated EAE lesions differed in their composition but not in their localization within the CNS. While Th1 lesions contained IFN-γ, but no IL-17 producing T cells, the T cells in Th17 lesions showed plasticity, substantially converting to IFN-γ producing Th1-like cells. Th1 and Th17 cells differed drastically by their lytic potential. Th1 but not Th17 cells lysed autoantigen presenting astrocytes and fibroblasts in vitro in a contact-dependent manner. In contrast, Th17 cells acquired cytotoxic potential only after antigenic stimulation and conversion to IFN-γ producing Th1 phenotype. Conclusions Our data demonstrate that both Th1 and Th17 lineages possess the ability to induce CNS autoimmunity but can function with complementary as well as differential pathogenic mechanisms. We propose that Th17-like cells producing IL-17 are required for the generation of atypical EAE whereas IFN-γ producing Th1 cells induce

  11. CXCR4 Antagonist AMD3100 Modulates Claudin Expression and Intestinal Barrier Function in Experimental Colitis

    PubMed Central

    Xia, Xian-Ming; Wang, Fang-Yu; Zhou, Ju; Hu, Kai-Feng; Li, Su-Wen; Zou, Bing-Bing

    2011-01-01

    Ulcerative colitis is a gastrointestinal disorder characterized by local inflammation and impaired epithelial barrier. Previous studies demonstrated that CXC chemokine receptor 4 (CXCR4) antagonists could reduce colonic inflammation and mucosal damage in dextran sulfate sodium (DSS)-induced colitis. Whether CXCR4 antagonist has action on intestinal barrier and the possible mechanism, is largely undefined. In the present study, the experimental colitis was induced by administration of 5% DSS for 7 days, and CXCR4 antagonist AMD3100 was administered intraperitoneally once daily during the study period. For in vitro study, HT-29/B6 colonic cells were treated with cytokines or AMD3100 for 24 h until assay. DSS-induced colitis was characterized by morphologic changes in mice. In AMD3100-treated mice, epithelial destruction, inflammatory infiltration, and submucosal edema were markedly reduced, and the disease activity index was also significantly decreased. Increased intestinal permeability in DSS-induced colitis was also significantly reduced by AMD3100. The expressions of colonic claudin-1, claudin-3, claudin-5, claudin-7 and claudin-8 were markedly decreased after DSS administration, whereas colonic claudin-2 expression was significantly decreased. Treatment with AMD3100 prevented all these changes. However, AMD3100 had no influence on claudin-3, claudin-5, claudin-7 and claudin-8 expression in HT-29/B6 cells. Cytokines as TNF-α, IL-6, and IFN-γ increased apoptosis and monolayer permeability, inhibited the wound-healing and the claudin-3, claudin-7 and claudin-8 expression in HT-29/B6 cells. We suggest that AMD3100 acted on colonic claudin expression and intestinal barrier function, at least partly, in a cytokine-dependent pathway. PMID:22073304

  12. Intravenous Mesenchymal Stem Cells Improve Survival and Motor Function in Experimental Amyotrophic Lateral Sclerosis

    PubMed Central

    Uccelli, Antonio; Milanese, Marco; Principato, Maria Cristina; Morando, Sara; Bonifacino, Tiziana; Vergani, Laura; Giunti, Debora; Voci, Adriana; Carminati, Enrico; Giribaldi, Francesco; Caponnetto, Claudia; Bonanno, Giambattista

    2012-01-01

    Despite some advances in the understanding of amyotrophic lateral sclerosis (ALS) pathogenesis, significant achievements in treating this disease are still lacking. Mesenchymal stromal (stem) cells (MSCs) have been shown to be effective in several models of neurological disease. To determine the effects of the intravenous injection of MSCs in an ALS mouse model during the symptomatic stage of disease, MSCs (1 × 106) were intravenously injected in mice expressing human superoxide dismutase 1 (SOD1) carrying the G93A mutation (SOD1/G93A) presenting with experimental ALS. Survival, motor abilities, histology, oxidative stress markers and [3H]d-aspartate release in the spinal cord were investigated. MSC injection in SOD1/G93A mice improved survival and motor functions compared with saline-injected controls. Injected MSCs scantly home to the central nervous system and poorly engraft. We observed a reduced accumulation of ubiquitin agglomerates and of activated astrocytes and microglia in the spinal cord of MSC-treated SOD1/G93A mice, with no changes in the number of choline acetyltransferase– and glutamate transporter type 1–positive cells. MSC administration turned around the upregulation of metallothionein mRNA expression and of the activity of the antioxidant enzyme glutathione S-transferase, both associated with disease progression. Last, we observed that MSCs reverted both spontaneous and stimulus-evoked neuronal release of [3H]d-aspartate, a marker of endogenous glutamate, which is upregulated in SOD1/G93A mice. These findings suggest that intravenous administration of MSCs significantly improves the clinical outcome and pathological scores of mutant SOD1/G93A mice, thus providing the rationale for their exploitation for the treatment of ALS. PMID:22481270

  13. Effects of ketanserin on experimental colitis in mice and macrophage function

    PubMed Central

    XIAO, JUNHUA; SHAO, LIMEI; SHEN, JIAQING; JIANG, WEILIANG; FENG, YUN; ZHENG, PING; LIU, FEI

    2016-01-01

    Ketanserin is a selective 5-hydroxytryptamine (serotonin)-2A receptor (5-HT2AR) antagonist. Studies have suggested that ketanserin exerts anti-inflammatory effects independent of the baroreflex; however, the mechanisms involved remain unclear. Thus, in the present study, we aimed to evaluate the effects of ketanserin in colitis and the possible underlying mechanisms. The expression of 5-HT2AR was assessed in the colon tissues of patients with inflammatory bowel disease (IBD) and in mice with dextran sodium sulfate (DSS)-induced colitis. The therapeutic potential of ketanserin was investigated in the mice with colitis. In the colon tissue samples from the patients with IBD, a high expression level of 5-HT2AR was observed. Treatment with ketanserin attenuated the progression of experimental colitis in the mice, as indicated by body weight assessment, colon length, histological scores and cytokine release. The colonic macrophages from the ketanserin-treated mice with colitis exhibited a decreased production of inflammatory cytokines, with M2 polarization and impaired migration. The knockdown of 5-HT2AR using siRNA partly abolished the inhibitory effects of ketanserin on the release of pro-inflammatory cytokines in bone marrow derived-macrophages (BMDMs), thus demonstrating that the inhibitory effects of ketanserin on the production of inflammatory cytokines are partly dependent on 5-HT2AR. Ketanserin also inhibited the activation of nuclear factor-κB (NF-κB) in BMDMs. In conclusion, the findings of the present study demonstrate that ketanserin alleviates colitis. Its anti-inflammatory effects may be due to the promotion of the anti-inflammatory function of macrophages through 5-HT2AR/NF-κB. PMID:26865503

  14. Modeling functional Magnetic Resonance Imaging (fMRI) experimental variables in the Ontology of Experimental Variables and Values (OoEVV)

    PubMed Central

    Burns, Gully A.P.C.; Turner, Jessica A.

    2015-01-01

    Neuroimaging data is raw material for cognitive neuroscience experiments, leading to scientific knowledge about human neurological and psychological disease, language, perception, attention and ultimately, cognition. The structure of the variables used in the experimental design defines the structure of the data gathered in the experiments; this in turn structures the interpretative assertions that may be presented as experimental conclusions. Representing these assertions and the experimental data which support them in a computable way means that they could be used in logical reasoning environments, i.e. for automated meta-analyses, or linking hypotheses and results across different levels of neuroscientific experiments. Therefore, a crucial first step in being able to represent neuroimaging results in a clear, computable way is to develop representations for the scientific variables involved in neuroimaging experiments. These representations should be expressive, computable, valid, extensible, and easy-to-use. They should also leverage existing semantic standards to interoperate easily with other systems. We present an ontology design pattern called the Ontology of Experimental Variables and Values (OoEVV). This is designed to provide a lightweight framework to capture mathematical properties of data, with appropriate ‘hooks’ to permit linkage to other ontology-driven projects (such as the Ontology of Biomedical Investigations, OBI). We instantiate the OoEVV system with a small number of functional Magnetic Resonance Imaging datasets, to demonstrate the system’s ability to describe the variables of a neuroimaging experiment. OoEVV is designed to be compatible with the XCEDE neuroimaging data standard for data collection terminology, and with the Cognitive Paradigm Ontology (CogPO) for specific reasoning elements of neuroimaging experimental designs. PMID:23684873

  15. Curriculum, Classroom Practices, and Tool Design in the Learning of Functions through Technology-Aided Experimental Approaches

    ERIC Educational Resources Information Center

    Lagrange, J. B.

    2005-01-01

    The paper starts from classroom situations about the study of a functional relationship with help of technological tools as a "transposition" of experimental approaches from research mathematical practices. It considers the limitation of this transposition in existing curricula and practices based on the use of non-symbolic software like dynamic…

  16. Effects of estrogen on functional and neurological recovery after spinal cord injury: An experimental study with rats

    PubMed Central

    Letaif, Olavo Biraghi; Cristante, Alexandre Fogaça; de Barros Filho, Tarcísio Eloy Pessoa; Ferreira, Ricardo; dos Santos, Gustavo Bispo; da Rocha, Ivan Dias; Marcon, Raphael Martus

    2015-01-01

    OBJECTIVES: To evaluate the functional and histological effects of estrogen as a neuroprotective agent after a standard experimentally induced spinal cord lesion. METHODS: In this experimental study, 20 male Wistar rats were divided into two groups: one group with rats undergoing spinal cord injury (SCI) at T10 and receiving estrogen therapy with 17-beta estradiol (4mg/kg) immediately following the injury and after the placement of skin sutures and a control group with rats only subjected to SCI. A moderate standard experimentally induced SCI was produced using a computerized device that dropped a weight on the rat's spine from a height of 12.5 mm. Functional recovery was verified with the Basso, Beattie and Bresnahan scale on the 2nd, 7th, 14th, 21st, 28th, 35th and 42nd days after injury and by quantifying the motor-evoked potential on the 42nd day after injury. Histopathological evaluation of the SCI area was performed after euthanasia on the 42nd day. RESULTS: The experimental group showed a significantly greater functional improvement from the 28th to the 42nd day of observation compared to the control group. The experimental group showed statistically significant improvements in the motor-evoked potential compared with the control group. The results of pathological histomorphometry evaluations showed a better neurological recovery in the experimental group, with respect to the proportion and diameter of the quantified nerve fibers. CONCLUSIONS: Estrogen administration provided benefits in neurological and functional motor recovery in rats with SCI beginning at the 28th day after injury. PMID:26598084

  17. Measuring the Subjective Value of Risky and Ambiguous Options using Experimental Economics and Functional MRI Methods

    PubMed Central

    Levy, Ifat; Rosenberg Belmaker, Lior; Manson, Kirk; Tymula, Agnieszka; Glimcher, Paul W.

    2012-01-01

    Most of the choices we make have uncertain consequences. In some cases the probabilities for different possible outcomes are precisely known, a condition termed "risky". In other cases when probabilities cannot be estimated, this is a condition described as "ambiguous". While most people are averse to both risk and ambiguity1,2, the degree of those aversions vary substantially across individuals, such that the subjective value of the same risky or ambiguous option can be very different for different individuals. We combine functional MRI (fMRI) with an experimental economics-based method3 to assess the neural representation of the subjective values of risky and ambiguous options4. This technique can be now used to study these neural representations in different populations, such as different age groups and different patient populations. In our experiment, subjects make consequential choices between two alternatives while their neural activation is tracked using fMRI. On each trial subjects choose between lotteries that vary in their monetary amount and in either the probability of winning that amount or the ambiguity level associated with winning. Our parametric design allows us to use each individual's choice behavior to estimate their attitudes towards risk and ambiguity, and thus to estimate the subjective values that each option held for them. Another important feature of the design is that the outcome of the chosen lottery is not revealed during the experiment, so that no learning can take place, and thus the ambiguous options remain ambiguous and risk attitudes are stable. Instead, at the end of the scanning session one or few trials are randomly selected and played for real money. Since subjects do not know beforehand which trials will be selected, they must treat each and every trial as if it and it alone was the one trial on which they will be paid. This design ensures that we can estimate the true subjective value of each option to each subject. We then

  18. Emodin enhances alveolar epithelial barrier function in rats with experimental acute pancreatitis

    PubMed Central

    Xia, Xian-Ming; Wang, Fang-Yu; Wang, Zhen-Kai; Wan, Hai-Jun; Xu, Wen-An; Lu, Heng

    2010-01-01

    AIM: To investigate the effect of emodin on expression of claudin-4, claudin-5 and occludin, as well as the alveolar epithelial barrier in rats with pancreatitis induced by sodium taurocholate. METHODS: Experimental pancreatitis was induced by retrograde injection of 5% sodium taurocholate into the biliopancreatic duct. Emodin was injected via the external jugular vein 3 h after induction of acute pancreatitis. Rats from sham operation group and acute pancreatitis group were injected with normal saline (an equivalent volume as emodin) at the same time point. Samples of lung and serum were obtained 6 h after drug administration. Pulmonary morphology was examined with HE staining. Pulmonary edema was estimated by measuring water content in lung tissue samples. Tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) level were measured by enzyme-linked immunospecific assay. Serum amylase and pulmonary myeloperoxidase (MPO) activity were detected by spectrophotometry. Alveolar epithelial barrier was assessed by pulmonary dye extravasation. Expression of claudin-4, claudin-5 and occludin in lung tissue samples was examined by immunohistology, quantitative real-time reverse transcription polymerase chain reaction and Western blotting analysis, respectively. RESULTS: Pancreatitis-associated lung injury was characterized by pulmonary edema, leukocyte infiltration, alveolar collapse, and elevated serum amylase level. The pulmonary damage, pulmonary pathological scores, serum amylase and MPO activity, TNF-α and IL-6 levels, and wet/dry ratio were decreased in rats after treatment with emodin. Immunostaining of claudin-4, claudin-5 and occludin was detected in lung tissue samples from rats in sham operation group, which was distributed in alveolar epithelium, vascular endothelium, and bronchial epithelium, respectively. The mRNA and protein expression levels of claudin-4, claudin-5 and occludin in lung tissue samples were markedly decreased, the expression level of

  19. System and methods for wide-field quantitative fluorescence imaging during neurosurgery.

    PubMed

    Valdes, Pablo A; Jacobs, Valerie L; Wilson, Brian C; Leblond, Frederic; Roberts, David W; Paulsen, Keith D

    2013-08-01

    We report an accurate, precise and sensitive method and system for quantitative fluorescence image-guided neurosurgery. With a low-noise, high-dynamic-range CMOS array, we perform rapid (integration times as low as 50 ms per wavelength) hyperspectral fluorescence and diffuse reflectance detection and apply a correction algorithm to compensate for the distorting effects of tissue absorption and scattering. Using this approach, we generated quantitative wide-field images of fluorescence in tissue-simulating phantoms for the fluorophore PpIX, having concentrations and optical absorption and scattering variations over clinically relevant ranges. The imaging system was tested in a rodent model of glioma, detecting quantitative levels down to 20 ng/ml. The resulting performance is a significant advance on existing wide-field quantitative imaging techniques, and provides performance comparable to a point-spectroscopy probe that has previously demonstrated significant potential for improved detection of malignant brain tumors during surgical resection. PMID:23903142

  20. Reconfigurable MRI-guided robotic surgical manipulator: prostate brachytherapy and neurosurgery applications.

    PubMed

    Su, Hao; Iordachita, Iulian I; Yan, Xiaoan; Cole, Gregory A; Fischer, Gregory S

    2011-01-01

    This paper describes a modular design approach for robotic surgical manipulator under magnetic resonance imaging (MRI) guidance. The proposed manipulator provides 2 degree of freedom (DOF) Cartesian motion and 2-DOF pitch and yaw motion. Primarily built up with dielectric materials, it utilizes parallel mechanism and is compact in size to fit into the limited space of close-bore MRI scanner. It is ideal for needle based surgical procedures which usually require positioning and orientation control for accurate imaging plane alignment. Specifically, this mechanism is easily reconfigurable to over constrained manipulator structure which provides 2-DOF Cartesian motion by simple structure modification. This modular manipulator integrated with different end-effector modules is investigated for prostate brachytherapy and neurosurgery applications as preliminary evaluation. PMID:22254754

  1. Telemedicine in neurosurgery using international digital telephone services between Japan and Malaysia--technical note.

    PubMed

    Houkin, K; Fukuhara, S; Selladurai, B M; Zurin, A A; Ishak, M; Kuroda, S; Abe, H

    1999-10-01

    A new image transmission and teleconference system using international digital telephone services was established between Japan and Malaysia. This new system consists of an ordinary personal computer, image scanner, and terminal adapter for digital telephone lines. The quality of images transferred using this system was high enough for diagnosis and discussion except for images such as radiographs requiring huge data transfer. Transmission of one image took approximately 20 seconds. The cost performance was almost equal to the conventional mailing system. The most remarkable advantage of this new system is the high quality of transferred images, the cost and time performance, and security of the medical information. New communication systems using international digital networks including the internet may allow re-distribution of medical resources between advanced countries and developing countries in neurosurgery. PMID:10598447

  2. [Nicolai Guleke--the founder and pioneer of neurosurgery in Thuringia].

    PubMed

    Dube, W; Besel, R; Maier, F

    1989-01-01

    After the representation of the biographical data and stages of development in the life of Prof. Nikolai Guleke (25th April 1878 to 4th April 1958) it is shown on the basis of his services as a director of the Surgical University Clinic in Jena how he deserved particularly well of the development of neurosurgery. Besides his skills in the surgical-technical field his close co-operation with the then director of the Neurological Clinic of the Jena University, Hans Berger, is appreciated as well as his scientific work, summarised in Volume III/1 of the ten volumes comprising surgical teachings by Kirschner "Interventions in the Cranium, Brain, at the Vertebral Column, the Spinal cord and the Branches of the N. trigeminus". Nikolai Guleke is considered to be an outstanding personality in the history of surgery of our country. PMID:2701914

  3. A novel registration method for image-guided neurosurgery system based on stereo vision.

    PubMed

    An, Yong; Wang, Manning; Song, Zhijian

    2015-01-01

    This study presents a novel spatial registration method of Image-guided neurosurgery system (IGNS) based on stereo-vision. Images of the patient's head are captured by a video camera, which is calibrated and tracked by an optical tracking system. Then, a set of sparse facial data points are reconstructed from them by stereo vision in the patient space. Surface matching method is utilized to register the reconstructed sparse points and the facial surface reconstructed from preoperative images of the patient. Simulation experiments verified the feasibility of the proposed method. The proposed method it is a new low-cost and easy-to-use spatial registration method for IGNS, with good prospects for clinical application. PMID:26406100

  4. Preoperative Steroid Use and the Risk of Infectious Complications After Neurosurgery

    PubMed Central

    Merkler, Alexander E.; Saini, Vaishali; Kamel, Hooman; Stieg, Philip E.

    2014-01-01

    Background and Purpose: The association between preoperative corticosteroid use and infectious complications after neurosurgical procedures is unclear. We aim to determine whether corticosteroids increase the risk of infectious complications after neurosurgery. Methods: We examined the association between preoperative corticosteroid use and postoperative infectious complications in a cohort of adults who underwent a neurosurgical procedure between 2005 and 2010 at centers participating in the National Surgical Quality Improvement Program. Corticosteroid use was defined as at least 10 days of oral or parental therapy in the 30 days prior to surgery. Our primary outcome was a composite of any infectious complications occurring within 30 days of surgery. We used propensity score analysis to examine the independent association between preoperative corticosteroid use and postoperative infections. Results: Among 26 634 neurosurgical procedures, 1228 (4.61%, 95% confidence interval [CI], 4.36-4.86) were preceded by preoperative corticosteroid use and 1469 (5.52%; 95% CI, 5.24-5.79) were followed by postoperative infections. In a propensity score analysis controlling for comorbidities, illness severity, and preexisting preoperative infections, corticosteroid use was independently associated with subsequent postoperative infections (odds ratio, 1.38; 95% CI, 1.11-1.70). Our results were unchanged in sensitivity analyses controlling for central nervous system tumors or active treatment with chemotherapy. Conclusion: Our results suggest that preoperative corticosteroid use is associated with an increased risk of infectious complications after neurosurgery. These findings may aid physicians with preoperative treatment decisions and risk stratification. Future randomized trials are needed to guide preoperative use of corticosteroids in this population. PMID:24707336

  5. Application of underwater shock wave and laser-induced liquid jet to neurosurgery

    NASA Astrophysics Data System (ADS)

    Tominaga, T.; Nakagawa, A.; Hirano, T.; Sato, J.; Kato, K.; Hosseini, S. H. R.; Takayama, K.

    2006-03-01

    Paper deals with applications of underwater shock waves to medicine. A historical development of underwater shock wave generation by using pulsed Ho:YAG laser beam irradiation in water is briefly described and an overview is given regarding potential applications of shock waves to neuro-surgery. The laser beam irradiation in a liquid-filled catheter produces water vapor bubble and shock waves intermittently produces micro-liquid jets in a controlled fashion from the exit of the catheter. Correlations between shock dynamics and bubble dynamics are emphasized. To optimize the jet motion, results of basic parametric studies are briefly presented. The liquid jet discharged from the catheter exit has an impulse high enough to clearly exhibit effectiveness for various medical purposes. In liquid jets we observed reasonably strong shock waves and hence invented a compact shock generator aiming to apply to microsurgery. We applied it to a rat's bone window and developed an effective method of brain protection against shock loading. The insertion of Gore-Tex® sheet is found to attenuate shock waves drastically even for very short stand off distance and its physical mechanism is clarified. The laser-induced liquid jet (LILJ) is successfully applied to soft tissue dissection. Animal experiments were performed and results of histological observations are presented in details. Results of animal experiments revealed that LILJ can sharply dissect soft tissue with a minimum amount of liquid consumption, while blood vessels larger than 0.2 mm in diameter are preserved. Shock waves and LILJ have a potential to be indispensable tools in neuro-surgery.

  6. Paediatric day-case neurosurgery in a resource challenged setting: Pattern and practice

    PubMed Central

    Owojuyigbe, Afolabi Muyiwa; Komolafe, Edward O.; Adenekan, Anthony T.; Dada, Muyiwa A.; Onyia, Chiazor U.; Ogunbameru, Ibironke O.; Owagbemi, Oluwafemi F.; Talabi, Ademola O.; Faponle, Fola A.

    2016-01-01

    Background: It has been generally observed that children achieve better convalescence in the home environment especially if discharged same day after surgery. This is probably due to the fact that children generally tend to feel more at ease in the home environment than in the hospital setting. Only few tertiary health institutions provide routine day-case surgery for paediatric neurosurgical patients in our sub-region. Objective: To review the pattern and practice of paediatric neurosurgical day-cases at our hospital. Patients and Methods: A prospective study of all paediatric day-case neurosurgeries carried out between June 2011 and June 2014. Results: A total of 53 patients (34 males and 19 females) with age ranging from 2 days to 14 years were seen. Majority of the patients (77.4%) presented with congenital lesions, and the most common procedure carried out was spina bifida repair (32%) followed by ventriculoperitoneal shunt insertion (26.4%) for hydrocephalus. Sixty-eight percentage belonged to the American Society of Anesthesiologists physical status class 2, whereas the rest (32%) belonged to class 1. General anaesthesia was employed in 83% of cases. Parenteral paracetamol was used for intra-operative analgesia for most of the patients. Two patients had post-operative nausea and vomiting and were successfully managed. There was no case of emergency re-operation, unplanned admission, cancellation or mortality. Conclusion: Paediatric day-case neurosurgery is feasible in our environment. With careful patient selection and adequate pre-operative preparation, good outcome can be achieved. PMID:27251657

  7. Integrating risk management data in quality improvement initiatives within an academic neurosurgery department.

    PubMed

    McLaughlin, Nancy; Garrett, Matthew C; Emami, Leila; Foss, Sarah K; Klohn, Johanna L; Martin, Neil A

    2016-01-01

    OBJECT While malpractice litigation has had many negative impacts on health care delivery systems, information extracted from lawsuits could potentially guide toward venues to improve care. The authors present a comprehensive review of lawsuits within a tertiary academic neurosurgical department and report institutional and departmental strategies to mitigate liability by integrating risk management data with quality improvement initiatives. METHODS The Comprehensive Risk Intelligence Tool database was interrogated to extract claims/suits abstracts concerning neurosurgical cases that were closed from January 2008 to December 2012. Variables included demographics of the claimant, type of procedure performed (if any), claim description, insured information, case outcome, clinical summary, contributing factors and subfactors, amount incurred for indemnity and expenses, and independent expert opinion in regard to whether the standard of care was met. RESULTS During the study period, the Department of Neurosurgery received the most lawsuits of all surgical specialties (30 of 172), leading to a total incurred payment of $4,949,867. Of these lawsuits, 21 involved spinal pathologies and 9 cranial pathologies. The largest group of suits was from patients with challenging medical conditions who underwent uneventful surgeries and postoperative courses but filed lawsuits when they did not see the benefits for which they were hoping; 85% of these claims were withdrawn by the plaintiffs. The most commonly cited contributing factors included clinical judgment (20 of 30), technical skill (19 of 30), and communication (6 of 30). CONCLUSIONS While all medical and surgical subspecialties must deal with the issue of malpractice and liability, neurosurgery is most affected both in terms of the number of suits filed as well as monetary amounts awarded. To use the suits as learning tools for the faculty and residents and minimize the associated costs, quality initiatives addressing the

  8. Future directions in 3-dimensional imaging and neurosurgery: stereoscopy and autostereoscopy.

    PubMed

    Christopher, Lauren A; William, Albert; Cohen-Gadol, Aaron A

    2013-01-01

    Recent advances in 3-dimensional (3-D) stereoscopic imaging have enabled 3-D display technologies in the operating room. We find 2 beneficial applications for the inclusion of 3-D imaging in clinical practice. The first is the real-time 3-D display in the surgical theater, which is useful for the neurosurgeon and observers. In surgery, a 3-D display can include a cutting-edge mixed-mode graphic overlay for image-guided surgery. The second application is to improve the training of residents and observers in neurosurgical techniques. This article documents the requirements of both applications for a 3-D system in the operating room and for clinical neurosurgical training, followed by a discussion of the strengths and weaknesses of the current and emerging 3-D display technologies. An important comparison between a new autostereoscopic display without glasses and current stereo display with glasses improves our understanding of the best applications for 3-D in neurosurgery. Today's multiview autostereoscopic display has 3 major benefits: It does not require glasses for viewing; it allows multiple views; and it improves the workflow for image-guided surgery registration and overlay tasks because of its depth-rendering format and tools. Two current limitations of the autostereoscopic display are that resolution is reduced and depth can be perceived as too shallow in some cases. Higher-resolution displays will be available soon, and the algorithms for depth inference from stereo can be improved. The stereoscopic and autostereoscopic systems from microscope cameras to displays were compared by the use of recorded and live content from surgery. To the best of our knowledge, this is the first report of application of autostereoscopy in neurosurgery. PMID:23254802

  9. An American medical student's experience in global neurosurgery: both in their infancy.

    PubMed

    Magarik, Jordan; Kavolus, Joseph; Louis, Robert

    2012-01-01

    There are only three fully trained neurosurgeons to care for Tanzania's population of more than 41 million people. Madaktari was founded in 2006 to serve as a physician training partnership to establish more self-sufficient health care through education and training. Medical students play a valuable role in Madaktari as they are primarily responsible for collecting postneurosurgical outcome data on operations performed by Tanzanian physicians trained by our organization. In addition, medical students represent the future of global medicine. Thus, it is important to determine the extent that Madaktari has affected student interest in global health. Our purpose in this article is to explore one student's experience working in global neurosurgery while working with Madaktari. In addition we attempted to determine the effect Madaktari may play on the future medical careers of eight medical student volunteers. To determine that effect we conducted a six-question online survey of medical student volunteers. We received responses from four of our eight medical student volunteers, all of whom stated they had a good or excellent experience volunteering with Madaktari and that their experience further increased their desire to incorporate global health into their careers. After working with Madaktari nearly half of the medical student volunteers have pursued or will be pursuing year-long funded global health research during their medical school careers. Madaktari is not only pioneering a path toward increased and more independent neurosurgical capabilities in Tanzania, but it is also helping foster increased interest and participation among U.S. medical students in global neurosurgery. PMID:22079820

  10. Endoscopic neurosurgery.

    PubMed

    Auer, L M; Holzer, P; Ascher, P W; Heppner, F

    1988-01-01

    This paper describes an ultrasound-guided, laser-assisted, and TV-controlled endoscopic technique which has been used so far in 133 patients for a variety of intracranial lesions. Following CT or MRI image reconstruction, and a decision on the placement of a 1 cm or a 2 cm burrhole, a 1 cm 5.0 mHz or 7.5 mHz intraoperative ultrasound probe is used to direct the endoscope from the burrhole to the target area. A 22.5 cm long rigid endoscope tube with an outer diameter of 6 mm with an inbuilt suction irrigation system, Neodymium Yag laser with 600 micron Quartz glass-fibre and an inlet for various microinstruments is then introduced. The attachment of a TV camera to the ocular lens allows the operator to control further surgical steps in the target area via the TV screen and thus warrants sterility in the operating field. The technique has been used for evacuation of 77 spontaneous intracerebral haematomas (lobar, putaminal, thalamic), 8 traumatic intracerebral haematomas, 13 ventricular haematomas, 8 cerebellar haematomas and 1 brainstem haematoma. Total or subtotal evacuation was achieved in 33% of intracerebral haematomas, removal of more than 50% of the clot in 55%. Twenty-four brain tumours (12 ventricular, 12 cystic cerebral or cerebellar tumours) were operated on for biopsy, evacuation of cyst, resection or removal of the cyst wall and/or laser irradiation of solid tumour or the inner cyst wall of cystic tumours. The complication rate probably related to surgery was 1.6%, morbidity 1.6%, mortality 0%. This high-tec endoscopic technique with its minimal surgical trauma and short operation time can be recommended as a low-risk alternative to conventional neurosurgical techniques. PMID:3278501

  11. Experimental determination of single-event upset (SEU) as a function of collected charge in bipolar integrated circuits

    NASA Technical Reports Server (NTRS)

    Zoutendyk, J. A.; Malone, C. J.; Smith, L. S.

    1984-01-01

    Single-Event Upset (SEU) in bipolar integrated circuits (ICs) is caused by charge collection from ion tracks in various regions of a bipolar transistor. This paper presents experimental data which have been obtained wherein the range-energy characteristics of heavy ions (Br) have been utilized to determine the cross section for soft-error generation as a function of charge collected from single-particle tracks which penetrate a bipolar static RAM. The results of this work provide a basis for the experimental verification of circuit-simulation SEU modeling in bipolar ICs.

  12. Experimental Research on Profile Control for Oil Displacement by Functional Polymer in Low Permeability Fractured Reservoir

    NASA Astrophysics Data System (ADS)

    Li, Li; Xiuting, Han; Lin, Meng

    Utilizing artificial fractured cores with low permeability, a physical simulation experiment on profile control for oil displacement was carried out. The result showed that 23.63% extra oil recovery was realized by functional polymer, and 29.05% extra oil recovery was realized by functional polymer with gas which is higher than water flooding alone. The experiment demonstrates that functional polymer is effective for enhance oil recovery for low permeability fractured reservoir significantly.

  13. Experimental and Theoretical Analysis of Nanotransport in Oligophenylene Dithiol Junctions as a Function of Molecular Length and Contact Work Function.

    PubMed

    Xie, Zuoti; Bâldea, Ioan; Smith, Christopher E; Wu, Yanfei; Frisbie, C Daniel

    2015-08-25

    We report the results of an extensive investigation of metal-molecule-metal tunnel junctions based on oligophenylene dithiols (OPDs) bound to several types of electrodes (M1-S-(C6H4)n-S-M2, with 1 ≤ n ≤ 4 and M1,2 = Ag, Au, Pt) to examine the impact of molecular length (n) and metal work function (Φ) on junction properties. Our investigation includes (1) measurements by scanning Kelvin probe microscopy of electrode work function changes (ΔΦ = ΦSAM - Φ) caused by chemisorption of OPD self-assembled monolayers (SAMs), (2) measurements of junction current-voltage (I-V) characteristics by conducting probe atomic force microscopy in the linear and nonlinear bias ranges, and (3) direct quantitative analysis of the full I-V curves. Further, we employ transition voltage spectroscopy (TVS) to estimate the energetic alignment εh = EF - EHOMO of the dominant molecular orbital (HOMO) relative to the Fermi energy EF of the junction. Where photoelectron spectroscopy data are available, the εh values agree very well with those determined by TVS. Using a single-level model, which we justify via ab initio quantum chemical calculations at post-density functional theory level and additional UV-visible absorption measurements, we are able to quantitatively reproduce the I-V measurements in the whole bias range investigated (∼1.0-1.5 V) and to understand the behavior of εh and Γ (contact coupling strength) extracted from experiment. We find that Fermi level pinning induced by the strong dipole of the metal-S bond causes a significant shift of the HOMO energy of an adsorbed molecule, resulting in εh exhibiting a weak dependence with the work function Φ. Both of these parameters play a key role in determining the tunneling attenuation factor (β) and junction resistance (R). Correlation among Φ, ΔΦ, R, transition voltage (Vt), and εh and accurate simulation provide a remarkably complete picture of tunneling transport in these prototypical molecular junctions. PMID

  14. An experimental study of the step-response function of ferrofluids as a function of particle volume fraction

    NASA Astrophysics Data System (ADS)

    Fannin, P. C.; Charles, S. W.

    1994-09-01

    Measurements are reported on the step-response function, F( t), or magnetisation decay of five ferrofluid samples of magnetite in Isopar M with packing fractions ranging from 0.019 to 0.115. An alternative to the conventional method of measuring magnetisation decay involving the use of dc fields is used, with F( t) being obtained by means of a technique which utilises complex susceptibility data. The presence of a particle size distribution is accounted for with a measure of the particle distribution in each sample being determined by means of the 'approximate ellipse' technique.

  15. Slow angled-descent forepaw grasping (SLAG): an innate behavioral task for identification of individual experimental mice possessing functional vision

    PubMed Central

    2013-01-01

    Background There is significant interest in the generation of improved assays to clearly identify experimental mice possessing functional vision, a property that could qualify mice for inclusion in behavioral and neuroscience studies. Widely employed current methods rely on mouse responses to visual cues in assays of reflexes, depth perception, or cognitive memory. However, commonly assessed mouse reflexes can sometimes be ambiguous in their expression, while depth perception assays are sometimes confounded by variation in anxiety responses and exploratory conduct. Furthermore, in situations where experimental groups vary in their cognitive memory capacity, memory assays may not be ideal for assessing differences in vision. Results We have optimized a non-invasive behavioral assay that relies on an untrained, innate response to identify individual experimental mice possessing functional vision: slow angled-descent forepaw grasping (SLAG). First, we verified that SLAG performance depends on vision and not olfaction. Next, all members of an age-ranged cohort of 158 C57BL/6 mice (57 wild-type, 101 knockout, age range 44–241 days) were assessed for functional vision using the SLAG test without training or conditioning. Subjecting the population to a second innate behavioral test, Dark Chamber preference, corroborated that the functional vision assessment of SLAG was valid. Conclusions We propose that the SLAG assay is immediately useful to quickly and clearly identify experimental mice possessing functional vision. SLAG is based on a behavioral readout with a significant innate component with no requirement for training. This will facilitate the selection of mice of known sighted status in vision-dependent experiments that focus on other types of behavior, neuroscience, and/or cognitive memory. PMID:23971729

  16. Altered contralateral sensorimotor system organization after experimental hemispherectomy: a structural and functional connectivity study

    PubMed Central

    Otte, Willem M; van der Marel, Kajo; van Meer, Maurits P A; van Rijen, Peter C; Gosselaar, Peter H; Braun, Kees P J; Dijkhuizen, Rick M

    2015-01-01

    Hemispherectomy is often followed by remarkable recovery of cognitive and motor functions. This reflects plastic capacities of the remaining hemisphere, involving large-scale structural and functional adaptations. Better understanding of these adaptations may (1) provide new insights in the neuronal configuration and rewiring that underlies sensorimotor outcome restoration, and (2) guide development of rehabilitation strategies to enhance recovery after hemispheric lesioning. We assessed brain structure and function in a hemispherectomy model. With MRI we mapped changes in white matter structural integrity and gray matter functional connectivity in eight hemispherectomized rats, compared with 12 controls. Behavioral testing involved sensorimotor performance scoring. Diffusion tensor imaging and resting-state functional magnetic resonance imaging were acquired 7 and 49 days post surgery. Hemispherectomy caused significant sensorimotor deficits that largely recovered within 2 weeks. During the recovery period, fractional anisotropy was maintained and white matter volume and axial diffusivity increased in the contralateral cerebral peduncle, suggestive of preserved or improved white matter integrity despite overall reduced white matter volume. This was accompanied by functional adaptations in the contralateral sensorimotor network. The observed white matter modifications and reorganization of functional network regions may provide handles for rehabilitation strategies improving functional recovery following large lesions. PMID:25966942

  17. Verbal Conditioning of Male and Female Schizophrenics as a Function of Experimenter Proximity

    ERIC Educational Resources Information Center

    Rierdan, Jill; Brooks, Robert

    1978-01-01

    Assess the effects of patient-experimenter proximity on schizophrenics' learning when the social class of the subjects, both schizophrenics and nonschizophrenics, and the verbal and nonverbal components of social reinforcement are controlled. Also tests males and females to determine whether sex of subjects moderates the responses of…

  18. Evidence-based neurosurgery. Basic concepts for the appraisal and application of scientific information to patient care (Part II).

    PubMed

    Esene, Ignatius N; Baeesa, Saleh S; Ammar, Ahmed

    2016-07-01

    Medical evidence is obtainable from approaches, which might be descriptive, analytic and integrative and ranked into levels of evidence, graded according to quality and summarized into strengths of recommendation. Sources of evidence range from expert opinions through well-randomized control trials to meta-analyses. The conscientious, explicit, and judicious use of current best evidence in making decisions related to the care of individual patients defines the concept of evidence-based neurosurgery (EBN). We reviewed reference books of clinical epidemiology, evidence-based practice and other previously related articles addressing principles of evidence-based practice in neurosurgery. Based on existing theories and models and our cumulative years of experience and expertise conducting research and promoting EBN, we have synthesized and presented a holistic overview of the concept of EBN. We have also underscored the importance of clinical research and its relationship to EBN. Useful electronic resources are provided. The concept of critical appraisal is introduced. PMID:27356649

  19. Functional rescue of experimental ischemic optic neuropathy with αB-crystallin

    PubMed Central

    Pangratz-Fuehrer, S; Kaur, K; Ousman, S S; Steinman, L; Liao, Y J

    2011-01-01

    Purpose Anterior ischemic optic neuropathy (AION) is an important cause of acute vision loss in adults, and there is no effective treatment. We studied early changes following experimental AION and tested the benefit of a potential treatment. Materials and Methods We induced experimental AION in adult mice and tested the effects of short-term (daily for 3 days) and long-term (every other day for 3 weeks) αB-crystallin (αBC) treatment using histological and serial intracranial flash visual evoked potential recordings. Results One day after experimental AION, there was swelling at the optic nerve (ON) head and increased expression of αBC, a small heat shock protein important in ischemia and inflammation. This upregulation coincided with microglial and astrocytic activation. Our hypothesis was that αBC may be part of the endogenous protective mechanism against injury, thus we tested the effects of αBC on experimental AION. Daily intraveneous or intravitreal αBC injections did not improve visual evoked potential amplitude or latency at days 1–2. However, αBC treatment decreased swelling and dampened the microglial and astrocytic activation on day 3. Longer treatment with intravenous αBC led to acceleration of visual evoked potential latency over 3 weeks, without improving amplitude. This latency acceleration did not correlate with increased retinal ganglion cell survival but did correlate with complete rescue of the ON oligodendrocytes, which are important for myelination. Conclusions We identified αBC as an early marker following experimental AION. Treatment with αBC enhanced this endogenous, post-ischemic response by decreasing microglial activation and promoting ON oligodendrocyte survival. PMID:21475310

  20. Subsonic Kernel-Function Flutter Analysis of a Highly Tapered Tail Surface and Comparison with Experimental Results

    NASA Technical Reports Server (NTRS)

    Walberg, Gerald D.

    1960-01-01

    A flutter analysis employing the kernel function for three-dimensional, subsonic, compressible flow is applied to a flutter-tested tail surface which has an aspect ratio of 3.5, a taper ratio of 0.15, and a leading-edge sweep of 30 deg. Theoretical and experimental results are compared at Mach numbers from 0.75 to 0.98. Good agreement between theoretical and experimental flutter dynamic pressures and frequencies is achieved at Mach numbers to 0.92. At Mach numbers from 0.92 to 0.98, however, a second solution to the flutter determinant results in a spurious theoretical flutter boundary which is at a much lower dynamic pressure and at a much higher frequency than the experimental boundary.

  1. Peptide-functionalized polymeric nanoparticles for active targeting of damaged tissue in animals with experimental autoimmune encephalomyelitis.

    PubMed

    Führmann, Tobias; Ghosh, Mousumi; Otero, Anthony; Goss, Ben; Dargaville, Tim R; Pearse, Damien D; Dalton, Paul D

    2015-08-18

    Increased permeability of blood vessels is an indicator for various injuries and diseases, including multiple sclerosis (MS), of the central nervous system. Nanoparticles have the potential to deliver drugs locally to sites of tissue damage, reducing the drug administered and limiting associated side effects, but efficient accumulation still remains a challenge. We developed peptide-functionalized polymeric nanoparticles to target blood clots and the extracellular matrix molecule nidogen, which are associated with areas of tissue damage. Using the induction of experimental autoimmune encephalomyelitis in rats to provide a model of MS associated with tissue damage and blood vessel lesions, all targeted nanoparticles were delivered systemically. In vivo data demonstrates enhanced accumulation of peptide functionalized nanoparticles at the injury site compared to scrambled and naive controls, particularly for nanoparticles functionalized to target fibrin clots. This suggests that further investigations with drug laden, peptide functionalized nanoparticles might be of particular interest in the development of treatment strategies for MS. PMID:26141613

  2. Anchoring Pd nanoclusters onto pristine and functionalized single-wall carbon nanotubes: A combined DFT and experimental study

    NASA Astrophysics Data System (ADS)

    Prasomsri, Teerawit; Shi, Dachuan; Resasco, Daniel E.

    2010-09-01

    The dispersion of Pd nanoclusters on single-wall carbon nanotubes (SWCNT) can be enhanced by creating defects on the nanotube walls, which lead to a stronger metal-support interaction. The ONIOM (DFT:MM) calculations show that the binding energy of Pd is significantly enhanced when the SWCNT surface is oxygen-functionalized, compared to the case of the pristine SWCNT surface. The electronic interaction of Pd atoms with oxygen at the defect sites results in a stronger bonding. These calculations are consistent with experimental measurements. Microscopy images clearly show that the functionalized SWCNT surface is much more effective than the pristine surface in anchoring Pd nanoclusters.

  3. CT10 NLO and NNLO Parton Distribution Functions from the Coordinated Theoretical-Experimental Project on QCD

    DOE Data Explorer

    Huston, Joey [Co-Spokesperson; Ownes, Joseph [Co-Spokesperson

    The Coordinated Theoretical-Experimental Project on QCD is a multi-institutional collaboration devoted to a broad program of research projects and cooperative enterprises in high-energy physics centered on Quantum Chromodynamics (QCD) and its implications in all areas of the Standard Model and beyond. The Collaboration consists of theorists and experimentalists at 18 universities and 5 national laboratories. More than 65 sets of Parton Distribution Functions are available for public access. Links to many online software tools, information about Parton Distribution Functions, papers, and other resources are also available.

  4. The Synthesis of Structural Responses Using Experimentally Measured Frequency Response Functions and Field Test Data

    SciTech Connect

    CAP,JEROME S.; NELSON,CURTIS F.

    2000-11-17

    This paper presents an analysis technique used to generate the structural response at locations not measured during the ejection of a captive-carried store. The ejection shock event is complicated by the fact that forces may be imparted to the store at eight distinct locations. The technique derives forcing functions by combining the initial field test data for a limited number of measurement locations with Frequency Response Functions (FRFs) measured using a traditional modal-type impact (tap) test at the same locations. The derived forcing functions were then used with tap test FRFs measured at additional locations of interest to produce the desired response data.

  5. Functional Analysis and Discovery of Microbial Genes Transforming Metallic and Organic Pollutants: Database and Experimental Tools

    SciTech Connect

    Lawrence P. Wackett; Lynda B.M. Ellis

    2004-12-09

    Microbial functional genomics is faced with a burgeoning list of genes which are denoted as unknown or hypothetical for lack of any knowledge about their function. The majority of microbial genes encode enzymes. Enzymes are the catalysts of metabolism; catabolism, anabolism, stress responses, and many other cell functions. A major problem facing microbial functional genomics is proposed here to derive from the breadth of microbial metabolism, much of which remains undiscovered. The breadth of microbial metabolism has been surveyed by the PIs and represented according to reaction types on the University of Minnesota Biocatalysis/Biodegradation Database (UM-BBD): http://umbbd.ahc.umn.edu/search/FuncGrps.html The database depicts metabolism of 49 chemical functional groups, representing most of current knowledge. Twice that number of chemical groups are proposed here to be metabolized by microbes. Thus, at least 50% of the unique biochemical reactions catalyzed by microbes remain undiscovered. This further suggests that many unknown and hypothetical genes encode functions yet undiscovered. This gap will be partly filled by the current proposal. The UM-BBD will be greatly expanded as a resource for microbial functional genomics. Computational methods will be developed to predict microbial metabolism which is not yet discovered. Moreover, a concentrated effort to discover new microbial metabolism will be conducted. The research will focus on metabolism of direct interest to DOE, dealing with the transformation of metals, metalloids, organometallics and toxic organics. This is precisely the type of metabolism which has been characterized most poorly to date. Moreover, these studies will directly impact functional genomic analysis of DOE-relevant genomes.

  6. The Krigifier: A Procedure for Generating Pseudorandom Nonlinear Objective Functions for Computational Experimentation

    NASA Technical Reports Server (NTRS)

    Trosset, Michael W.

    1999-01-01

    Comprehensive computational experiments to assess the performance of algorithms for numerical optimization require (among other things) a practical procedure for generating pseudorandom nonlinear objective functions. We propose a procedure that is based on the convenient fiction that objective functions are realizations of stochastic processes. This report details the calculations necessary to implement our procedure for the case of certain stationary Gaussian processes and presents a specific implementation in the statistical programming language S-PLUS.

  7. Effects of Plant Diversity, Functional Group Composition, and Fertilization on Soil Microbial Properties in Experimental Grassland

    PubMed Central

    Strecker, Tanja; Barnard, Romain L.; Niklaus, Pascal A.; Scherer-Lorenzen, Michael; Weigelt, Alexandra; Scheu, Stefan; Eisenhauer, Nico

    2015-01-01

    Background Loss of biodiversity and increased nutrient inputs are two of the most crucial anthropogenic factors driving ecosystem change. Although both received considerable attention in previous studies, information on their interactive effects on ecosystem functioning is scarce. In particular, little is known on how soil biota and their functions are affected by combined changes in plant diversity and fertilization. Methodology/Principal Findings We investigated the effects of plant diversity, functional community composition, and fertilization on the biomass and respiration of soil microbial communities in a long-term biodiversity experiment in semi-natural grassland (Jena Experiment). Plant species richness enhanced microbial basal respiration and microbial biomass, but did not significantly affect microbial specific respiration. In contrast, the presence of legumes and fertilization significantly decreased microbial specific respiration, without altering microbial biomass. The effect of legumes was superimposed by fertilization as indicated by a significant interaction between the presence of legumes and fertilization. Further, changes in microbial stoichiometry (C-to-N ratio) and specific respiration suggest the presence of legumes to reduce N limitation of soil microorganisms and to modify microbial C use efficiency. Conclusions/Significance Our study highlights the role of plant species and functional group diversity as well as interactions between plant community composition and fertilizer application for soil microbial functions. Our results suggest soil microbial stoichiometry to be a powerful indicator of microbial functioning under N limited conditions. Although our results support the notion that plant diversity and fertilizer application independently affect microbial functioning, legume effects on microbial N limitation were superimposed by fertilization, indicating significant interactions between the functional composition of plant communities and

  8. Role of Inhibitors of Apoptosis Proteins in Testicular Function and Male Fertility: Effects of Polydeoxyribonucleotide Administration in Experimental Varicocele.

    PubMed

    Minutoli, Letteria; Arena, Salvatore; Antonuccio, Pietro; Romeo, Carmelo; Bitto, Alessandra; Magno, Carlo; Rinaldi, Mariagrazia; Micali, Antonio; Irrera, Natasha; Pizzino, Gabriele; Galfo, Federica; Squadrito, Francesco; Altavilla, Domenica; Marini, Herbert

    2015-01-01

    Neuronal apoptosis inhibitory protein (NAIP) and survivin might play an important role in testicular function. We investigated the effect of PDRN, an agonist of adenosine A2A receptor, on testicular NAIP and survivin expression in an experimental model of varicocele. After the creation of experimental varicocele (28 days), adolescent male Sprague-Dawley rats were randomized to one of the following treatments lasting 21 days: vehicle, PDRN (8 mg/kg i.p., daily), PDRN + 3,7-dimethyl-propargylxanthine (DMPX, a specific adenosine A2A-receptor antagonist, 0.1 mg/kg i.p., daily), varicocelectomy, and varicocelectomy + PDRN (8 mg/kg i.p., daily). Sham-operated animals were used as controls. Animals were then euthanized and testis expression of NAIP and survivin was evaluated through qRT-PCR, western blot, and immunohistochemical analysis. Spermatogenetic activity was also assessed. NAIP and survivin expressions were significantly reduced following varicocele induction when compared to sham animals whereas PDRN-treated rats showed an increase in NAIP and survivin levels. Immunohistochemistry revealed an enhanced expression of NAIP and survivin with a characteristic pattern of cellular localization following PDRN treatment. Moreover, administration of PDRN significantly restored spermatogenic function in varicocele rats. PDRN may represent a rational therapeutic option for accelerating recovery from depressed testicular function through a strategic modulation of apoptosis in experimental varicocele. PMID:26347229

  9. Role of Inhibitors of Apoptosis Proteins in Testicular Function and Male Fertility: Effects of Polydeoxyribonucleotide Administration in Experimental Varicocele

    PubMed Central

    Minutoli, Letteria; Arena, Salvatore; Antonuccio, Pietro; Romeo, Carmelo; Bitto, Alessandra; Magno, Carlo; Rinaldi, Mariagrazia; Micali, Antonio; Irrera, Natasha; Pizzino, Gabriele; Galfo, Federica; Squadrito, Francesco; Altavilla, Domenica; Marini, Herbert

    2015-01-01

    Neuronal apoptosis inhibitory protein (NAIP) and survivin might play an important role in testicular function. We investigated the effect of PDRN, an agonist of adenosine A2A receptor, on testicular NAIP and survivin expression in an experimental model of varicocele. After the creation of experimental varicocele (28 days), adolescent male Sprague-Dawley rats were randomized to one of the following treatments lasting 21 days: vehicle, PDRN (8 mg/kg i.p., daily), PDRN + 3,7-dimethyl-propargylxanthine (DMPX, a specific adenosine A2A-receptor antagonist, 0.1 mg/kg i.p., daily), varicocelectomy, and varicocelectomy + PDRN (8 mg/kg i.p., daily). Sham-operated animals were used as controls. Animals were then euthanized and testis expression of NAIP and survivin was evaluated through qRT-PCR, western blot, and immunohistochemical analysis. Spermatogenetic activity was also assessed. NAIP and survivin expressions were significantly reduced following varicocele induction when compared to sham animals whereas PDRN-treated rats showed an increase in NAIP and survivin levels. Immunohistochemistry revealed an enhanced expression of NAIP and survivin with a characteristic pattern of cellular localization following PDRN treatment. Moreover, administration of PDRN significantly restored spermatogenic function in varicocele rats. PDRN may represent a rational therapeutic option for accelerating recovery from depressed testicular function through a strategic modulation of apoptosis in experimental varicocele. PMID:26347229

  10. Automated genomic context analysis and experimental validation platform for discovery of prokaryote transcriptional regulator functions

    SciTech Connect

    Martí-Arbona, Ricardo; Mu, Fangping; Nowak-Lovato, Kristy L.; Wren, Melinda S.; Unkefer, Clifford J.; Unkefer, Pat J.

    2014-12-18

    The clustering of genes in a pathway and the co-location of functionally related genes is widely recognized in prokaryotes. We used these characteristics to predict the metabolic involvement for a Transcriptional Regulator (TR) of unknown function, identified and confirmed its biological activity. A software tool that identifies the genes encoded within a defined genomic neighborhood for the subject TR and its homologs was developed. The output lists of genes in the genetic neighborhoods, their annotated functions, the reactants/products, and identifies the metabolic pathway in which the encoded-proteins function. When a set of TRs of known function was analyzed, we observed that their homologs frequently had conserved genomic neighborhoods that co-located the metabolically related genes regulated by the subject TR. We postulate that TR effectors are metabolites in the identified pathways; indeed the known effectors were present. We analyzed Bxe_B3018 from Burkholderia xenovorans, a TR of unknown function and predicted that this TR was related to the glycine, threonine and serine degradation. We tested the binding of metabolites in these pathways and for those that bound, their ability to modulate TR binding to its specific DNA operator sequence. Using rtPCR, we confirmed that methylglyoxal was an effector of Bxe_3018.

  11. Automated genomic context analysis and experimental validation platform for discovery of prokaryote transcriptional regulator functions

    DOE PAGESBeta

    Martí-Arbona, Ricardo; Mu, Fangping; Nowak-Lovato, Kristy L.; Wren, Melinda S.; Unkefer, Clifford J.; Unkefer, Pat J.

    2014-12-18

    The clustering of genes in a pathway and the co-location of functionally related genes is widely recognized in prokaryotes. We used these characteristics to predict the metabolic involvement for a Transcriptional Regulator (TR) of unknown function, identified and confirmed its biological activity. A software tool that identifies the genes encoded within a defined genomic neighborhood for the subject TR and its homologs was developed. The output lists of genes in the genetic neighborhoods, their annotated functions, the reactants/products, and identifies the metabolic pathway in which the encoded-proteins function. When a set of TRs of known function was analyzed, we observedmore » that their homologs frequently had conserved genomic neighborhoods that co-located the metabolically related genes regulated by the subject TR. We postulate that TR effectors are metabolites in the identified pathways; indeed the known effectors were present. We analyzed Bxe_B3018 from Burkholderia xenovorans, a TR of unknown function and predicted that this TR was related to the glycine, threonine and serine degradation. We tested the binding of metabolites in these pathways and for those that bound, their ability to modulate TR binding to its specific DNA operator sequence. Using rtPCR, we confirmed that methylglyoxal was an effector of Bxe_3018.« less

  12. Inflammatory cell function in young rodents with experimental cholestasis: investigations of functional deficits, their etiology, and their reversibility.

    PubMed

    Roughneen, P T; Drath, D B; Kulkarni, A D; Kumar, S C; Andrassy, R J; Rowlands, B J

    1989-07-01

    Children with cholestasis are susceptible to infective complications. This may be attributable to impaired host defense. We postulated that cholestasis affects systemic polymorphonuclear leukocyte (PMN) function by impeding chemotaxis, phagocytosis, and superoxide release, which are all critical in eliciting an adequate immune response. Sprague Dawley rats (225 g) were assigned to three groups: bile duct ligated (BDL), sham (SH), and normal control (NC). On day 21 after operation, PMN and sera were isolated. Chemotactic response to C5a and FMLP (formyl-methionyl-leucyl-phenylalanine), superoxide release, and phagocytic uptake of 14C-labeled Staphylococcus aureus were performed on pooled PMN samples. Results were expressed as mean +/- SD. Serum bilirubin at day 21 was 6.3 +/- 2.9 v 0.1 +/- 0.1 and 0.1 +/- 0 mg/dL (P less than .01) in BDL, SH, and NC groups, respectively. Kinetic studies of PMN phagocytosis demonstrated impaired 14C S aureus uptake by BDL neutrophils at 60 (P less than .05), 90 (P less than .05), and 120 minutes (P less than .05) compared with SH and NC groups. No differences in PMN chemotactic response to C5a and FMLP was observed in BDL, SH and NC groups (43 +/- 14 v 40 +/- 12 and 33 +/- 1, and 43 +/- 20 v 43 +/- 14 and 28 +/- 1 cell per field, respectively). Zymosan stimulated superoxide release did not differ between groups (14.3 +/- 3.6 (BDL) v 15.1 +/- 8.7 (SH) and 12 +/- 2.0 (NC) nmol/30 min/mg cell protein, respectively. Thus, cholestasis impairs neutrophil phagocytosis in vitro.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2547052

  13. Experimental and theoretical investigations of functionalized boron nitride as electrode materials for Li-ion batteries

    SciTech Connect

    Zhang, Fan; Nemeth, Karoly; Bareño, Javier; Dogan, Fulya; Bloom, Ira D.; Shaw, Leon L.

    2016-01-01

    The feasibility of synthesizing functionalized h-BN (FBN) via the reaction between molten LiOH and solid h-BN is studied for the first time and its first ever application as an electrode material in Li-ion batteries is evaluated. Density functional theory (DFT) calculations are performed to provide mechanistic understanding of the possible electrochemical reactions derived from the FBN. Various materials characterizations reveal that the melt-solid reaction can lead to exfoliation and functionalization of h-BN simultaneously, while electrochemical analysis proves that the FBN can reversibly store charges through surface redox reactions with good cycle stability and coulombic efficiency. DFT calculations have provided physical insights into the observed electrochemical properties derived from the FBN.

  14. The influence of iron deficiency on the functioning of skeletal muscles: experimental evidence and clinical implications.

    PubMed

    Stugiewicz, Magdalena; Tkaczyszyn, Michał; Kasztura, Monika; Banasiak, Waldemar; Ponikowski, Piotr; Jankowska, Ewa A

    2016-07-01

    Skeletal and respiratory myopathy not only constitutes an important pathophysiological feature of heart failure and chronic obstructive pulmonary disease, but also contributes to debilitating symptomatology and predicts worse outcomes in these patients. Accumulated evidence from laboratory experiments, animal models, and interventional studies in sports medicine suggests that undisturbed systemic iron homeostasis significantly contributes to the effective functioning of skeletal muscles. In this review, we discuss the role of iron status for the functioning of skeletal muscle tissue, and highlight iron deficiency as an emerging therapeutic target in chronic diseases accompanied by a marked muscle dysfunction. PMID:26800032

  15. Glucans synthesized in situ in experimental salivary pellicle function as specific binding sites for Streptococcus mutans.

    PubMed Central

    Schilling, K M; Bowen, W H

    1992-01-01

    Many researchers have suggested that the role of glucan-mediated interactions in the adherence of Streptococcus mutans is restricted to accumulation of this cariogenic bacterium following its sucrose (i.e., glucan)-independent binding to saliva-coated tooth surfaces. However, the presence of enzymatically active glucosyltransferase in salivary pellicle suggests that glucans could also promote the initial adherence of S. mutans to the teeth. In the present study, the commonly used hydroxyapatite adherence assay was modified to include the incorporation of glucosyltransferase and the synthesis of glucans in situ on saliva-coated hydroxyapatite beads. Several laboratory strains and clinical isolates of S. mutans were examined for their ability to adhere to experimental pellicles, either with or without the prior formation of glucans in situ. Results showed that most strains of S. mutans bound stereospecifically to glucans synthesized in pellicle. Inhibition studies with various polysaccharides and fungal dextranase indicated that alpha 1,6-linked glucose residues were of primary importance in the glucan binding observed. Scanning electron microscopic analysis showed direct binding of S. mutans to hydroxyapatite surface-associated polysaccharide and revealed no evidence of trapping or cell-to-cell binding. S. mutans strains also attached to host-derived structures in experimental pellicles, and the data suggest that the bacterial adhesins which recognize salivary binding sites were distinct from glucan-binding adhesins. Furthermore, glucans formed in experimental pellicles appeared to mask the host-derived components. These results support the concept that glucans synthesized in salivary pellicle can promote the selective adherence of the cariogenic streptococci which colonize human teeth. Images PMID:1530843

  16. [Early and Delayed Effects of Radio Frequency Electromagnetic Fields on the Reproductive Function and Functional Status of the Offspring of Experimental Animals].

    PubMed

    Shibkova, D Z; Shilkova, T V; Ovchinnikova, A V

    2015-01-01

    The aim of our experimental research was to study the impact of radio frequency electromagnetic fields (RF EMF) on the reproductive function of male and female mice of CBA in 2 models of exposure, as well as on the morphofunctional state of progeny of irradiated animals. It was found that RF EMF under conditions of repeated short-term exposures (within 5 days for 10 minutes at PES 1.2 mW/cm2) affects the course of pregnancy in female mice, the number of litters, fertility and preservation of offspring, morphometric characteristics of the offspring of experimental animals at different models of irradiation (exposure of animals to RF EMF prior to mating and during pregnancy). PMID:26863782

  17. Electronic and optical response of Ru(II) complexes functionalized by methyl, carboxylate groups: joint theoretical and experimental study

    SciTech Connect

    Tretiak, Sergei

    2008-01-01

    New photovoltaic and photocatalysis applications have been recently proposed based on the hybrid Ru(II)-bipyridine-complex/semiconductor quantum dot systems. In order to attach the complex to the surface of a semiconductor, a linking bridge - a carboxyl group - is added to one or two of the 2,2{prime}-bipyridine ligands. Such changes in the ligand structure, indeed, affect electronic and optical properties and consequently, the charge transfer reactivity of Ru-systems. In this study, we apply both theoretical and experimental approaches to analyze the effects brought by functionalization of bipyridine ligands with the methyl, carboxyl, and carboxilate groups on the electronic structure and optical response of the Ru(II) bipyridine complex. First principle calculations based on density functional theory (DFT) and linear response time dependent density functional theory (TDDFT) are used to simulate the ground and excited-state structures of functionalized Ru-complexes in the gas phase, as well as in acetonitrile solution. In addition, an inelaborate Frenkel exciton model is used to explain the optical activity and splitting patterns of the low-energy excited states. All theoretical results nicely complement experimental absorption spectra of Ru-complexes and contribute to their interpretation. We found that the carboxyl group breaks the degeneracy of two low-energy optically bright excited states and red-shifts the absorption spectrum, while leaves ionization and affinity energies of complexes almost unchanged. Experimental studies show a high probability of deprotonation of the carbboxyl group in the Ru-complexes resulted in a slight blue shift and decrease of intensities of the low energy absorption peaks. Comparison of experimental and theoretical linear response spectra of deprotanated complexes demonstrate strong agreement when acetonitrile solvent is used in simulations. A polar solvent is found to play an important role in calculations of optical spectra: it

  18. EXPERIMENTAL DETERMINATION OF CONTAMINANT METAL MOBILITY AS A FUNCTION OF TEMPERATURE, TIME, AND SOLUTION CHEMISTRY

    EPA Science Inventory

    We propose to determine the geochemical processes that control the mobility of Sr in the presence of clays (kaolinite, montmorillonite) and iron hydroxides (goethite) as a function of temperature, pH, and time. The objective of this work is to determine the fundamental data neede...

  19. Knockout of silent information regulator 2 (SIRT2) preserves neurological function after experimental stroke in mice.

    PubMed

    Krey, Lea; Lühder, Fred; Kusch, Kathrin; Czech-Zechmeister, Bozena; Könnecke, Birte; Fleming Outeiro, Tiago; Trendelenburg, George

    2015-12-01

    Sirtuin-2 (Sirt2) is a member of the NAD(+)-dependent protein deacetylase family. Various members of the sirtuin class have been found to be involved in processes related to longevity, regulation of inflammation, and neuroprotection. Induction of Sirt2 mRNA was found in the whole hemisphere after experimental stroke in a recent screening approach. Moreover, Sirt2 protein is highly expressed in myelin-rich brain regions after stroke. To examine the effects of Sirt2 on ischemic stroke, we induced transient focal cerebral ischemia in adult male Sirt2-knockout and wild-type mice. Two stroke models with different occlusion times were applied: a severe ischemia (45 minutes of middle cerebral artery occlusion (MCAO)) and a mild one (15 minutes of MCAO), which was used to focus on subcortical infarcts. Neurological deficit was determined at 48 hours after 45 minutes of MCAO, and up to 7 days after induction of 15 minutes of cerebral ischemia. In contrast to recent data on Sirt1, Sirt2(-/-) mice showed less neurological deficits in both models of experimental stroke, with the strongest manifestation after 48 hours of reperfusion. However, we did not observe a significant difference of stroke volumes or inflammatory cell count between Sirt2-deficient and wild-type mice. Thus we postulate that Sirt2 mediates myelin-dependent neuronal dysfunction during the early phase after ischemic stroke. PMID:26219598

  20. Experimental and theoretical spectroscopic studies of anticancer drug rosmarinic acid using HF and density functional theory

    NASA Astrophysics Data System (ADS)

    Mariappan, G.; Sundaraganesan, N.; Manoharan, S.

    2012-11-01

    In this work, we reported a combined experimental and theoretical study on molecular structure, vibrational spectra and NBO analysis of anticancer drug of rosmarinic acid. The optimized molecular structure, atomic charges, vibrational frequencies, natural bond orbital analysis and ultraviolet-visible spectral interpretation of rosmarinic acid have been studied by performing HF and DFT/B3LYP/6-31G(d,p) level of theory. The FT-IR (solid and solution phase), FT-Raman (solid phase) spectra were recorded in the region 4000-400 and 3500-50 cm-1, respectively. The UV-Visible absorption spectra of the compound that dissolved in ethanol were recorded in the range of 200-800 nm. The scaled wavenumbers are compared with the experimental values. The difference between the observed and scaled wavenumber values of most of the fundamentals is very small. The formation of hydrogen bond was investigated in terms of the charge density by the NBO calculations. Based on the UV spectra and TD-DFT calculations, the electronic structure and the assignments of the absorption bands were carried out. Besides, molecular electrostatic potential (MEP), frontier molecular orbitals (FMO) analysis were investigated using theoretical calculations.

  1. Continuous and noninvasive hemoglobin monitoring reduces red blood cell transfusion during neurosurgery: a prospective cohort study.

    PubMed

    Awada, Wael N; Mohmoued, Maher F; Radwan, Tarek M; Hussien, Gomaa Z; Elkady, Hany W

    2015-12-01

    Continuous, noninvasive hemoglobin (SpHb) monitoring provides clinicians with the trending of changes in hemoglobin, which has the potential to alter red blood cell transfusion decision making. The objective of this study was to evaluate the impact of SpHb monitoring on blood transfusions in high blood loss surgery. In this prospective cohort study, eligible patients scheduled for neurosurgery were enrolled into either a Control Group or an intervention group (SpHb Group). The Control Group received intraoperative hemoglobin monitoring by intermittent blood sampling when there was an estimated 15% blood loss. If the laboratory value indicated a hemoglobin level of ≤10 g/dL, a red blood cell transfusion was started and continued until the estimated blood loss was replaced and a laboratory hemoglobin value was >l0 g/dL. In the SpHb Group patients were monitored with a Radical-7 Pulse CO-Oximeter for continuous noninvasive hemoglobin values. Transfusion was started when the SpHb value fell to ≤l0 g/dL and was continued until the SpHb was ≥l0 g/dL. Blood samples were taken pre and post transfusion. Percent of patients transfused, average amount of blood transfused in those who received transfusions and the delay time from the hemoglobin reading of <10 g/dL to the start of transfusion (transfusion delay) were compared between groups. The trending ability of SpHb, and the bias and precision of SpHb compared to the laboratory hemoglobin were calculated. Compared to the Control Group, the SpHb Group had fewer units of blood transfused (1.0 vs 1.9 units for all patients; p ≤ 0.001, and 2.3 vs 3.9 units in patients receiving transfusions; p ≤ 0.0 l), fewer patients receiving >3 units (32 vs 73%; p ≤ 0.01) and a shorter time to transfusion after the need was established (9.2 ± 1.7 vs 50.2 ± 7.9 min; p ≤ 0.00 l). The absolute accuracy of SpHb was 0.0 ± 0.8 g/dL and trend accuracy yielded a coefficient of determination of 0.93. Adding SpHb monitoring to

  2. Parental Evaluation of a Nurse Practitioner-Developed Pediatric Neurosurgery Website

    PubMed Central

    Vogel, Tina Kovacs; Kleib, Manal; Davidson, Sandra J

    2016-01-01

    Background Parents often turn to the Internet to seek health information about their child’s diagnosis and condition. Information, support, and resources regarding pediatric neurosurgery are scarce, hard to find, and difficult to comprehend. To address this gap, a pediatric nurse practitioner designed a website called the Neurosurgery Kids Fund (NKF). Analyzing the legitimacy of the NKF website for parents seeking health information and fulfilling their social and resource needs is critical to the website’s future development and success. Objective To explore parental usage of the NKF website, track visitor behavior, evaluate usability and design, establish ways to improve user experience, and identify ways to redesign the website. The aim of this study was to assess and evaluate whether a custom-designed health website could meet parents’ health information, support, and resource needs. Methods A multimethod approach was used. Google Analytic usage reports were collected and analyzed for the period of April 23, 2013, to November 30, 2013. Fifty-two online questionnaires that targeted the website’s usability were collected between June 18, 2014, and July 30, 2014. Finally, a focus group was conducted on August 20, 2014, to explore parents’ perceptions and user experiences. Findings were analyzed using an inductive content analysis approach. Results There were a total of 2998 sessions and 8818 page views, with 2.94 pages viewed per session, a 56.20% bounce rate, an average session duration of 2 minutes 24 seconds, and a 56.24% new sessions rate. Results from 52 eligible surveys included that the majority of NKF users were Caucasian (90%), females (92%), aged 36-45 years (48%), with a university or college degree or diploma (69%). Half plan to use the health information. Over half reported turning to the Internet for health information and spending 2 to 4 hours a day online. The most common reasons for using the NKF website were to (1) gather information

  3. Striatal Cholinergic Interneurons Control Motor Behavior and Basal Ganglia Function in Experimental Parkinsonism.

    PubMed

    Maurice, Nicolas; Liberge, Martine; Jaouen, Florence; Ztaou, Samira; Hanini, Marwa; Camon, Jeremy; Deisseroth, Karl; Amalric, Marianne; Kerkerian-Le Goff, Lydia; Beurrier, Corinne

    2015-10-27

    Despite evidence showing that anticholinergic drugs are of clinical relevance in Parkinson's disease (PD), the causal role of striatal cholinergic interneurons (CINs) in PD pathophysiology remains elusive. Here, we show that optogenetic inhibition of CINs alleviates motor deficits in PD mouse models, providing direct demonstration for their implication in parkinsonian motor dysfunctions. As neural correlates, CIN inhibition in parkinsonian mice differentially impacts the excitability of striatal D1 and D2 medium spiny neurons, normalizes pathological bursting activity in the main basal ganglia output structure, and increases the functional weight of the direct striatonigral pathway in cortical information processing. By contrast, CIN inhibition in non-lesioned mice does not affect locomotor activity, equally modulates medium spiny neuron excitability, and does not modify spontaneous or cortically driven activity in the basal ganglia output, suggesting that the role of these interneurons in motor function is highly dependent on dopamine tone. PMID:26489458

  4. Functional data analysis of experimental parameters obtained in PVA doped CdCl2 polymer composites

    NASA Astrophysics Data System (ADS)

    Prakash, M. B. Nanda; Urs, Gopal Krishne; Somashekar, R.

    2016-05-01

    Using solution casting method, PVA based polymer composites films with various concentrations of CdCl2 were prepared. Prepared polymer composites films were investigated using XRD. Crystallite size for different concentrations of CdCl2 are computed here using Williamson and Hall plot (WH plot), an in-house program developed by us. To correlate between two independent physical parameters size and conductivity, we have chosen functional data analysis to estimate the maxima and minima in these polymer composites systems.

  5. Experimental studies of mitochondrial function in CADASIL vascular smooth muscle cells

    SciTech Connect

    Viitanen, Matti; Sundström, Erik; Baumann, Marc; Tikka, Saara

    2013-02-01

    Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy (CADASIL) is a familiar fatal progressive degenerative disorder characterized by cognitive decline, and recurrent stroke in young adults. Pathological features include a dramatic reduction of brain vascular smooth muscle cells and severe arteriopathy with the presence of granular osmophilic material in the arterial walls. Here we have investigated the cellular and mitochondrial function in vascular smooth muscle cell lines (VSMCs) established from CADASIL mutation carriers (R133C) and healthy controls. We found significantly lower proliferation rates in CADASIL VSMC as compared to VSMC from controls. Cultured CADASIL VSMCs were not more vulnerable than control cells to a number of toxic substances. Morphological studies showed reduced mitochondrial connectivity and increased number of mitochondria in CADASIL VSMCs. Transmission electron microscopy analysis demonstrated increased irregular and abnormal mitochondria in CADASIL VSMCs. Measurements of mitochondrial membrane potential (Δψ{sub m}) showed a lower percentage of fully functional mitochondria in CADASIL VSMCs. For a number of genes previously reported to be changed in CADASIL VSMCs, immunoblotting analysis demonstrated a significantly reduced SOD1 expression. These findings suggest that alteration of proliferation and mitochondrial function in CADASIL VSMCs might have an effect on vital cellular functions important for CADASIL pathology. -- Highlights: ► CADASIL is an inherited disease of cerebral vascular cells. ► Mitochondrial dysfunction has been implicated in the pathogenesis of CADASIL. ► Lower proliferation rates in CADASIL VSMC. ► Increased irregular and abnormal mitochondria and lower mitochondrial membrane potential in CADASIL VSMCs. ► Reduced mitochondrial connectivity and increased number of mitochondria in CADASIL VSMCs.

  6. A curious experiment: the paradigm switch from observation and speculation to experimentation, in the understanding of neuromuscular function and disease.

    PubMed

    Pearn, John

    2002-08-01

    The four-link chain of the motor unit represents the contemporary end-point of some two millennia of evolving knowledge in neuroscience. The paradigm shift in neuromuscular epistemology occurred in the mid-17th century. In 1666, the newly graduated Dutch doctor, Jan Swammerdam (1637-1680) published his former investigations of dissected nerve-muscle preparations. These experiments comprised the quantum leap from observation and speculation, to that of experimentation in the field of neuroanatomy and neurophysiology. In what he termed 'A Curious Experiment' he also described the phenomenon of intrinsic muscle excitability - "I cannot observe that the muscle in the living animal ever absolutely ceases from all motion". Eighty years later (1752), von Haller demonstrated experimentally that irritability (contractility) was an intrinsic property of all muscular tissue; and distinguished between the sensibility of nerve impulses and the irritability of muscular contraction. This experimental progression from Swammerdam to von Haller culminated in 1850, when Claude Bernard's studies in experimental pharmacology confirmed that muscle was a functional unit, independent of any electrical innervation via its supplying nerve. This account comprises an audit of Swammerdam's work in the perspective of neuromuscular knowledge. PMID:12117487

  7. Deuteron induced reactions on Ho and La: Experimental excitation functions and comparison with code results

    NASA Astrophysics Data System (ADS)

    Hermanne, A.; Adam-Rebeles, R.; Tarkanyi, F.; Takacs, S.; Csikai, J.; Takacs, M. P.; Ignatyuk, A.

    2013-09-01

    Activation products of rare earth elements are gaining importance in medical and technical applications. In stacked foil irradiations, followed by high resolution gamma spectroscopy, the cross-sections for production of 161,165Er, 166gHo on 165Ho and 135,137m,137g,139Ce, 140La, 133m,133g,cumBa and 136Cs on natLa targets were measured up to 50 MeV. Reduced uncertainty is obtained by simultaneous remeasurement of the 27Al(d,x)24,22Na monitor reactions over the whole energy range. A comparison with experimental literature values and results from updated theoretical codes (ALICE-D, EMPIRE-D and the TENDL2012 online library) is discussed.

  8. Results of drug correction of structural and functional changes in the gingiva in experimental gastroduodenitis.

    PubMed

    Romanenko, E G

    2014-04-01

    Morphological changes in the gingiva under the effect of drugs improving microcirculation were studied in pubertal Wistar rats with experimental gastroduodenitis. Chronic gastroduodenitis was induced by intragastric administration of 50% medical bile (1 ml/100 g body weight daily) for 40 days. The best medical correction was attained with altan and citrarginine. Morphologic studies showed signs of regeneration plastic activity of the epithelium, restructuring of the gingival lamina propria, and enlargement of the vascular bed area. Calcium-D3 Nycomed disordered the regeneration processes in the rat epithelium, because of calcium ion capacity to increase oxygen demand in tissues and cause destructive processes. Hence, pathogenetic drug correction of degenerative processes in the gingiva under conditions of chronic gastroduodenitis should include drugs promoting recovery of the microcirculatory bed, altan and citrarginine. PMID:24824716

  9. The Wave Function as Matter Density: Ontological Assumptions and Experimental Consequences

    NASA Astrophysics Data System (ADS)

    Jääskeläinen, Markku

    2015-06-01

    The wavefunction is the central mathematical entity of quantum mechanics, but it still lacks a universally accepted interpretation. Much effort is spent on attempts to probe its fundamental nature. Here I investigate the consequences of a matter ontology applied to spherical masses of constant bulk density. The governing equation for the center-of-mass wavefunction is derived and solved numerically. The ground state wavefunctions and resulting matter densities are investigated. A lowering of the density from its bulk value is found for low masses due to increased spatial spreading. A discussion of the possibility to experimentally observe these effects is given and the possible consequences for choosing an ontological interpretation for quantum mechanics are commented upon.

  10. Parthenogenetic dopamine neurons from primate embryonic stem cells restore function in experimental Parkinson's disease

    PubMed Central

    Lee, Hyojin; Patterson, Michaela; Reske-Nielsen, Casper; Yoshizaki, Takahito; Sonntag, Kai C.; Studer, Lorenz; Isacson, Ole

    2008-01-01

    The identity and functional potential of dopamine neurons derived in vitro from embryonic stem cells are critical for the development of a stem cell-based replacement therapy for Parkinson's disease. Using a parthenogenetic primate embryonic stem cell line, we have generated dopamine neurons that display persistent expression of midbrain regional and cell-specific transcription factors, which establish their proper identity and allow for their survival. We show here that transplantation of parthenogenetic dopamine neurons restores motor function in hemi-parkinsonian, 6-hydroxy-dopamine-lesioned rats. Exposure to Wnt5a and fibroblast growth factors (FGF) 20 and 2 at the final stage of in vitro differentiation enhanced the survival of dopamine neurons and, correspondingly, the extent of motor recovery of transplanted animals. Importantly for future development of clinical applications, dopamine neurons were post-mitotic at the time of transplantation and there was no tumour formation. These data provide proof for the concept that parthenogenetic stem cells are a suitable source of functional neurons for therapeutic applications. PMID:18669499

  11. Experimental warming alters potential function of the fungal community in boreal forest.

    PubMed

    Treseder, Kathleen K; Marusenko, Yevgeniy; Romero-Olivares, Adriana L; Maltz, Mia R

    2016-10-01

    Fungal community composition often shifts in response to warmer temperatures, which might influence decomposition of recalcitrant carbon (C). We hypothesized that evolutionary trade-offs would enable recalcitrant C-using taxa to respond more positively to warming than would labile C-using taxa. Accordingly, we performed a warming experiment in an Alaskan boreal forest and examined changes in the prevalence of fungal taxa. In a complementary field trial, we characterized the ability of fungal taxa to use labile C (glucose), intermediate C (hemicellulose or cellulose), or recalcitrant C (lignin). We also assigned taxa to functional groups (e.g., free-living filamentous fungi, ectomycorrhizal fungi, and yeasts) based on taxonomic identity. We found that response to warming varied most among taxa at the order level, compared to other taxonomic ranks. Among orders, ability to use lignin was significantly related to increases in prevalence in response to warming. However, the relationship was weak, given that lignin use explained only 9% of the variability in warming responses. Functional groups also differed in warming responses. Specifically, free-living filamentous fungi and ectomycorrhizal fungi responded positively to warming, on average, but yeasts responded negatively. Overall, warming-induced shifts in fungal communities might be accompanied by an increased ability to break down recalcitrant C. This change in potential function may reduce soil C storage under global warming. PMID:26836961

  12. Novel suppressive function of transitional 2 B cells in experimental arthritis.

    PubMed

    Evans, Jamie G; Chavez-Rueda, Karina A; Eddaoudi, Ayad; Meyer-Bahlburg, Almut; Rawlings, David J; Ehrenstein, Michael R; Mauri, Claudia

    2007-06-15

    The immune system contains natural regulatory cells important in the maintenance of tolerance. Although this suppressive function is usually attributed to CD4 regulatory T cells, recent reports have revealed an immunoregulatory role for IL-10-producing B cells in the context of several autoimmune diseases including collagen-induced arthritis. In the present study, we attribute this suppressive function to a B cell subset expressing high levels of CD21, CD23, and IgM, previously identified as transitional 2-marginal zone precursor (T2-MZP) B cells. T2-MZP B cells are present in the spleens of naive mice and increase during the remission phase of arthritis. Following adoptive transfer to immunized DBA/1 mice, T2-MZP B cells significantly prevented new disease and ameliorated established disease. The suppressive effect on arthritis was paralleled by an inhibition of Ag-specific T cell activation and a reduction in cells exhibiting Th1-type functional responses. We also provide evidence that this regulatory subset mediates its suppression through the secretion of suppressive cytokines and not by cell-to-cell contact. The ability to regulate an established immune response by T2-MZP B cells endows this subset of B cells with a striking and previously unrecognized immunoregulatory potential. PMID:17548625

  13. Experimental model of small subcortical infarcts in mice with long-lasting functional disabilities.

    PubMed

    Uchida, Hiroki; Sakata, Hiroyuki; Fujimura, Miki; Niizuma, Kuniyasu; Kushida, Yoshihiro; Dezawa, Mari; Tominaga, Teiji

    2015-12-10

    Small subcortical infarcts account for 25% of all ischemic strokes. Although once considered to be a small vessel disease with a favorable outcome, recent studies have reported relatively poor long-term prognoses following small subcortical infarcts. Limited pre-clinical modeling has hampered understanding of the etiology and development of treatments for this disease. Therefore, we attempted to develop a new experimental model of small subcortical infarcts in mice to investigate pathophysiological changes in the corticospinal tract and assess long-term behavioral performance. The vasoconstrictor peptide, endothlin-1 (ET-1), in combination with the nitric oxide synthase inhibitor, N(G)-nitro-l-arginine methyl ester (l-NAME), were injected into the internal capsule of mice. Histological and behavioral tests were performed 0-8 weeks after the injection. The ET-1/l-NAME injection resulted in severe neurological deficits that continued for up to 8 weeks. The loss of axons and myelin surrounded by reactive gliosis was identified in the region of the injection, in which the vasoconstriction of microvessels was also observed. Moreover, a tract-tracing study revealed an interruption in axonal flow at the internal capsule. The present model of small subcortical infarcts is unique and novel due to the reproduction of neurological deficits that continue for a long period, up to 8 weeks, as well as the use of mice as experimental animals. The reproducibility, simplicity, and easy adoptability make the present model highly appealing for use in further pre-clinical studies on small subcortical infarcts. PMID:26522346

  14. Advances in experimental methods for the elucidation of Pseudomonas syringae effector function with a focus on AvrPtoB

    PubMed Central

    Munkvold, Kathy R.; Martin, Gregory B.

    2010-01-01

    SUMMARY Pseudomonas syringae infects a wide range of plant species through the use of a type III secretion system. The effector proteins injected into the plant cell through this molecular syringe serve as promoters of disease by subverting the plant immune response to the benefit of the bacteria in the intercellular space. The targets and activities of a subset of effectors have been elucidated recently. In this article, we focus on the experimental approaches that have proved most successful in probing the molecular basis of effectors, ranging from loss-of-function to gain-of-function analyses utilizing several techniques for effector delivery into plants. In particular, we highlight how these diverse approaches have been applied to the study of one effector—AvrPtoB—a multifunctional protein with the ability to suppress both effector-triggered immunity and pathogen (or microbe)-associated molecular pattern-triggered immunity. Taken together, advances in this field illustrate the need for multiple experimental approaches when elucidating the function of a single effector. PMID:19849784

  15. Experimental response function of NaI(Tl) scintillation detector for gamma photons and tomographic measurements for defect detection

    NASA Astrophysics Data System (ADS)

    Sharma, Amandeep; Singh, Karamjit; Singh, Bhajan; Sandhu, B. S.

    2011-02-01

    The response function of gamma detector is an important factor for spectrum analysis because some photons and secondary electrons may escape the detector volume before fully depositing their energy, of course destroys the ideal delta function response. An inverse matrix approach, for unfolding of observed pulse-height distribution to a true photon spectrum, is used for construction of experimental response function by formulating a 40 × 40 matrix with bin mesh ( E1/2) of 0.025 (MeV) 1/2 for the present measurements. A tomographic scanner system, operating in a non-destructive and non-invasive way, is also presented for inspection of density variation in any object. The incoherent scattered intensity of 662 keV gamma photons, obtained by unfolding (deconvolution) the experimental pulse-height distribution of NaI(Tl) scintillation detector, provides the desired information. The method is quite sensitive, for showing inclusion of medium Z (atomic number) material (iron) in low Z material (aluminium) and detecting a void of ˜2 mm in size for iron block, to investigate the inhomogeneities in the object. Also, the grey scale images (using "MATLAB") are shown to visualise the presence of defects/inclusion in metal samples.

  16. A computer model of lens structure and function predicts experimental changes to steady state properties and circulating currents

    PubMed Central

    2013-01-01

    Background In a previous study (Vaghefi et al. 2012) we described a 3D computer model that used finite element modeling to capture the structure and function of the ocular lens. This model accurately predicted the steady state properties of the lens including the circulating ionic and fluid fluxes that are believed to underpin the lens internal microcirculation system. In the absence of a blood supply, this system brings nutrients to the core of the lens and removes waste products faster than would be achieved by passive diffusion alone. Here we test the predictive properties of our model by investigating whether it can accurately mimic the experimentally measured changes to lens steady-state properties induced by either depolarising the lens potential or reducing Na+ pump rate. Methods To mimic experimental manipulations reported in the literature, the boundary conditions of the model were progressively altered and the model resolved for each new set of conditions. Depolarisation of lens potential was implemented by increasing the extracellular [K+], while inhibition of the Na+ pump was stimulated by utilising the inherent temperature sensitivity of the pump and changing the temperature at which the model was solved. Results Our model correctly predicted that increasing extracellular [K+] depolarizes the lens potential, reducing and then reversing the magnitude of net current densities around the lens. While lowering the temperature reduced Na+ pump activity and caused a reduction in circulating current, it had a minimal effect on the lens potential, a result consistent with published experimental data. Conclusion We have shown that our model is capable of accurately simulating the effects of two known experimental manipulations on lens steady-state properties. Our results suggest that the model will be a valuable predictive tool to support ongoing studies of lens structure and function. PMID:23988187

  17. Monte Carlo calculation of the spatial response (Modulated Transfer Function) of a scintillation flat panel and comparison with experimental results

    NASA Astrophysics Data System (ADS)

    Juste, Belén; Miró, Rafael; Monasor, Paula; Verdú, Gumersindo

    2015-11-01

    Phosphor screens are commonly used in many X-ray imaging applications. The design and optimization of these detectors can be achieved using Monte Carlo codes to simulate radiation transport in scintillation materials and to improve the spatial response. This work presents an exhaustive procedure to measure the spatial resolution of a scintillation flat panel image and to evaluate the agreement with data obtained by simulation. To evaluate the spatial response we have used the Modulated Transfer Function (MTF) parameter. According to this, we have obtained the Line Spread Function (LSF) of the system since the Fourier Transform (FT) of the LSF gives the MTF. The experimental images were carried out using a medical X-ray tube (Toshiba E7299X) and a flat panel (Hammamatsu C9312SK). Measurements were based on the slit methodology experimental implementation, which measures the response of the system to a line. LSF measurements have been performed using a 0.2 mm wide lead slit superimposed over the flat panel. The detector screen was modelled with MCNP (version 6) Monte Carlo simulation code in order to analyze the effect of the acquisition setup configuration and to compare the response of scintillator screens with the experimental results. MCNP6 offers the possibility of studying the optical physics parameters (optical scattering and absorption coefficients) that occur in the phosphor screen. The study has been tested for different X-ray tube voltages, from 100 to 140 kV. An acceptable convergence between the MTF results obtained with MCNP6 and the experimental measurements have been obtained.

  18. Relationship of dietary iodide and drinking water disinfectants to thyroid function in experimental animals

    SciTech Connect

    Revis, N.W.; McCauley, P.; Holdsworth, G.

    1986-11-01

    The importance of dietary iodide on the reported hypothyroid effect of drinking water disinfectants on thyroid function was investigated. Previous studies have also showed differences in the relative sensitivity of pigeons and rabbits to chlorinated water. Pigeons and rabbits were exposed for 3 months to diets containing high (950 ppb) or low (300 ppb) levels of iodide and to drinking water containing two levels of chlorine. Results showed that the high-iodide diet prevented the hypothyroid effect observed in pigeons given the low-iodide diet and chlorinated drinking water. Similar trends were observed in rabbits exposed to the same treatment; however, significant hypothyroid effects were not observed in this animal model. The factor associated with the observed effect of dietary iodide on the chlorine-induced change in thyroid function is unknown, as is the relative sensitivity of rabbits and pigeons to the effect of chlorine. Several factors may explain the importance of dietary iodide and the relative sensitivity of these species. For example, the iodine formed by the known reaction of chlorine with iodide could result in a decrease in the plasma level of iodide because of the relative absorption rates of iodide and iodine in the intestinal tract, and the various types and concentrations of chloroorganics (metabolites) formed in the diet following the exposure of various dietary constituents to chlorine could affect the thyroid function. The former factor was investigated in the present studies. Results do not confirm a consistent, significant reduction in the plasma level of iodide in rabbits and pigeons exposed to chlorinated water and the low-iodide diet. The latter factor is being investigated.

  19. Experimental determination of frequency response function estimates for flexible joint industrial manipulators with serial kinematics

    NASA Astrophysics Data System (ADS)

    Saupe, Florian; Knoblach, Andreas

    2015-02-01

    Two different approaches for the determination of frequency response functions (FRFs) are used for the non-parametric closed loop identification of a flexible joint industrial manipulator with serial kinematics. The two applied experiment designs are based on low power multisine and high power chirp excitations. The main challenge is to eliminate disturbances of the FRF estimates caused by the numerous nonlinearities of the robot. For the experiment design based on chirp excitations, a simple iterative procedure is proposed which allows exploiting the good crest factor of chirp signals in a closed loop setup. An interesting synergy of the two approaches, beyond validation purposes, is pointed out.

  20. Recording stereoscopic 3D neurosurgery with a head-mounted 3D camera system.

    PubMed

    Lee, Brian; Chen, Brian R; Chen, Beverly B; Lu, James Y; Giannotta, Steven L

    2015-06-01

    Stereoscopic three-dimensional (3D) imaging can present more information to the viewer and further enhance the learning experience over traditional two-dimensional (2D) video. Most 3D surgical videos are recorded from the operating microscope and only feature the crux, or the most important part of the surgery, leaving out other crucial parts of surgery including the opening, approach, and closing of the surgical site. In addition, many other surgeries including complex spine, trauma, and intensive care unit procedures are also rarely recorded. We describe and share our experience with a commercially available head-mounted stereoscopic 3D camera system to obtain stereoscopic 3D recordings of these seldom recorded aspects of neurosurgery. The strengths and limitations of using the GoPro(®) 3D system as a head-mounted stereoscopic 3D camera system in the operating room are reviewed in detail. Over the past several years, we have recorded in stereoscopic 3D over 50 cranial and spinal surgeries and created a library for education purposes. We have found the head-mounted stereoscopic 3D camera system to be a valuable asset to supplement 3D footage from a 3D microscope. We expect that these comprehensive 3D surgical videos will become an important facet of resident education and ultimately lead to improved patient care. PMID:25620087

  1. Trajectory planning method for reduced patient risk in image-guided neurosurgery: concept and preliminary results

    NASA Astrophysics Data System (ADS)

    Shamir, Reuben R.; Joskowicz, Leo; Antiga, Luca; Foroni, Roberto I.; Shoshan, Yigal

    2010-02-01

    We present a new preoperative planning method to quantify and help reduce the risk associated with needle and tool insertion trajectories in image-guided keyhole neurosurgery. The goal is to quantify the risk of a proposed straight trajectory, and/or to find the trajectory with the lowest risk to nearby brain structures based on pre-operative CT/MRI images. The method automatically computes the risk associated with a given trajectory, or finds the trajectory with the lowest risk to nearby brain structures based on preoperative image segmentation and on a risk volume map. The surgeon can revise the suggested trajectory, add a new one using interactive 3D visualization, and obtain a quantitative risk measure. The trajectory risk is evaluated based on the tool placement uncertainty, on the proximity of critical brain structures, and on a predefined table of quantitative geometric risk measures. Our preliminary results on a clinical dataset with eight targets show a significant reduction in trajectory risk and a shortening of the preoperative planning time as compared to the conventional method.

  2. Neurosurgery simulation using non-linear finite element modeling and haptic interaction

    NASA Astrophysics Data System (ADS)

    Lee, Huai-Ping; Audette, Michel; Joldes, Grand R.; Enquobahrie, Andinet

    2012-02-01

    Real-time surgical simulation is becoming an important component of surgical training. To meet the realtime requirement, however, the accuracy of the biomechancial modeling of soft tissue is often compromised due to computing resource constraints. Furthermore, haptic integration presents an additional challenge with its requirement for a high update rate. As a result, most real-time surgical simulation systems employ a linear elasticity model, simplified numerical methods such as the boundary element method or spring-particle systems, and coarse volumetric meshes. However, these systems are not clinically realistic. We present here an ongoing work aimed at developing an efficient and physically realistic neurosurgery simulator using a non-linear finite element method (FEM) with haptic interaction. Real-time finite element analysis is achieved by utilizing the total Lagrangian explicit dynamic (TLED) formulation and GPU acceleration of per-node and per-element operations. We employ a virtual coupling method for separating deformable body simulation and collision detection from haptic rendering, which needs to be updated at a much higher rate than the visual simulation. The system provides accurate biomechancial modeling of soft tissue while retaining a real-time performance with haptic interaction. However, our experiments showed that the stability of the simulator depends heavily on the material property of the tissue and the speed of colliding objects. Hence, additional efforts including dynamic relaxation are required to improve the stability of the system.

  3. Qualitative Study: Exploring the Experiences of Family Caregivers within an Inpatient Neurology and Neurosurgery Hospital Setting.

    PubMed

    Khabarov, Dmytro; Dimitropoulos, Gina; McGillicuddy, Patti

    2015-11-01

    The aim of this study was to further understanding of what it means for family caregivers to be included in their relatives' care and identify what type of care they are providing. This study used a qualitative research design to recruit 12 participants, who were family caregivers, from the adult neurology and neurosurgery units at a hospital located in Toronto, Ontario, Canada. The data were collected using semistructured interviews, which were conducted in person and ranged between 30 and 60 minutes in length. Analysis of the data was conducted using phenomenological guidelines and principles. Upon review, the results indicated that the participants shared common experiences that were grouped into three main themes: (1) unfamiliarity with the hospital environment and procedures, (2) identifying the hidden realities of families and caregivers, and (3) strengthening collaborative dialogues and opportunities. Overall, this study exemplified that the need to continue to recognize family caregivers' experiences and their involvement is paramount in being able to understand how and in what way patient care can be better optimized collaboratively, during treatment delivery and recovery stages. PMID:26638505

  4. Image-guided system with miniature robot for precise positioning and targeting in keyhole neurosurgery.

    PubMed

    Joskowicz, L; Shamir, R; Freiman, M; Shoham, M; Zehavi, E; Umansky, F; Shoshan, Y

    2006-07-01

    This paper describes a novel image-guided system for precise automatic targeting in minimally invasive keyhole neurosurgery. The system consists of the MARS miniature robot fitted with a mechanical guide for needle, probe or catheter insertion. Intraoperatively, the robot is directly affixed to a head clamp or to the patient's skull. It automatically positions itself with respect to predefined targets in a preoperative CT/MRI image following an anatomical registration with an intraoperative 3D surface scan of the patient's facial features and registration jig. We present the system architecture, surgical protocol, custom hardware (targeting and registration jig), and software modules (preoperative planning, intraoperative execution, 3D surface scan processing, and three-way registration). We also describe a prototype implementation of the system and in vitro registration experiments. Our results indicate a system-wide target registration error of 1.7 mm (standard deviation = 0.7 mm), which is close to the required 1.0-1.5 mm clinical accuracy in many keyhole neurosurgical procedures. PMID:17038306

  5. Cost analysis of a project to digitize classic articles in neurosurgery*

    PubMed Central

    Bauer, Kathleen

    2002-01-01

    In summer 2000, the Cushing/Whitney Medical Library at Yale University began a demonstration project to digitize classic articles in neurosurgery from the late 1800s and early 1900s. The objective of the first phase of the project was to measure the time and costs involved in digitization, and those results are reported here. In the second phase, metadata will be added to the digitized articles, and the project will be publicized. Thirteen articles were scanned using optical character recognition (OCR) software, and the resulting text files were carefully proofread. Time for photocopying, scanning, and proofreading were recorded. This project achieved an average cost per item (total pages plus images) of $4.12, a figure at the high end of average costs found in other studies. This project experienced high costs for two reasons. First, the articles contained many images, which required extra processing. Second, the older fonts and the poor condition of many of these articles complicated the OCR process. The average article cost $84.46 to digitize. Although costs were high, the selection of historically important articles maximized the benefit gained from the investment in digitization. PMID:11999182

  6. Cost analysis of a project to digitize classic articles in neurosurgery.

    PubMed

    Bauer, Kathleen

    2002-04-01

    In summer 2000, the Cushing/Whitney Medical Library at Yale University began a demonstration project to digitize classic articles in neurosurgery from the late 1800s and early 1900s. The objective of the first phase of the project was to measure the time and costs involved in digitization, and those results are reported here. In the second phase, metadata will be added to the digitized articles, and the project will be publicized. Thirteen articles were scanned using optical character recognition (OCR) software, and the resulting text files were carefully proofread. Time for photocopying, scanning, and proofreading were recorded. This project achieved an average cost per item (total pages plus images) of $4.12, a figure at the high end of average costs found in other studies. This project experienced high costs for two reasons. First, the articles contained many images, which required extra processing. Second, the older fonts and the poor condition of many of these articles complicated the OCR process. The average article cost $84.46 to digitize. Although costs were high, the selection of historically important articles maximized the benefit gained from the investment in digitization. PMID:11999182

  7. Rivaling paradigms in psychiatric neurosurgery: adjustability versus quick fix versus minimal-invasiveness

    PubMed Central

    Müller, Sabine; Riedmüller, Rita; van Oosterhout, Ansel

    2015-01-01

    In the wake of deep brain stimulation (DBS) development, ablative neurosurgical procedures are seeing a comeback, although they had been discredited and nearly completely abandoned in the 1970s because of their unethical practice. Modern stereotactic ablative procedures as thermal or radiofrequency ablation, and particularly radiosurgery (e.g., Gamma Knife) are much safer than the historical procedures, so that a re-evaluation of this technique is required. The different approaches of modern psychiatric neurosurgery refer to different paradigms: microsurgical ablative procedures is based on the paradigm ‘quick fix,’ radiosurgery on the paradigm ‘minimal-invasiveness,’ and DBS on the paradigm ‘adjustability.’ From a mere medical perspective, none of the procedures is absolutely superior; rather, they have different profiles of advantages and disadvantages. Therefore, individual factors are crucial in decision-making, particularly the patients’ social situation, individual preferences, and individual attitudes. The different approaches are not only rivals, but also enriching mutually. DBS is preferable for exploring new targets, which may become candidates for ablative microsurgery or radiosurgery. PMID:25883557

  8. Fiber-based tissue identification for electrode placement in deep brain stimulation neurosurgery (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    DePaoli, Damon T.; Lapointe, Nicolas; Goetz, Laurent; Parent, Martin; Prudhomme, Michel; Cantin, Léo.; Galstian, Tigran; Messaddeq, Younès.; Côté, Daniel C.

    2016-03-01

    Deep brain stimulation's effectiveness relies on the ability of the stimulating electrode to be properly placed within a specific target area of the brain. Optical guidance techniques that can increase the accuracy of the procedure, without causing any additional harm, are therefore of great interest. We have designed a cheap optical fiber-based device that is small enough to be placed within commercially available DBS stimulating electrodes' hollow cores and that is capable of sensing biological information from the surrounding tissue, using low power white light. With this probe we have shown the ability to distinguish white and grey matter as well as blood vessels, in vitro, in human brain samples and in vivo, in rats. We have also repeated the in vitro procedure with the probe inserted in a DBS stimulating electrode and found the results were in good agreement. We are currently validating a second fiber optic device, with micro-optical components, that will result in label free, molecular level sensing capabilities, using CARS spectroscopy. The final objective will be to use this data in real time, during deep brain stimulation neurosurgery, to increase the safety and accuracy of the procedure.

  9. Knowledge modeling in image-guided neurosurgery: application in understanding intraoperative brain shift

    NASA Astrophysics Data System (ADS)

    Cohen-Adad, Julien; Paul, Perrine; Morandi, Xavier; Jannin, Pierre

    2006-03-01

    During an image-guided neurosurgery procedure, the neuronavigation system is subject to inaccuracy because of anatomical deformations which induce a gap between the preoperative images and their anatomical reality. Thus, the objective of many research teams is to succeed in quantifying these deformations in order to update preoperative images. Anatomical intraoperative deformations correspond to a complex spatio-temporal phenomenon. Our objective is to identify the parameters implicated in these deformations and to use these parameters as constrains for systems dedicated to updating preoperative images. In order to identify these parameters of deformation we followed the iterative methodology used for cognitive system conception: identification, conceptualization, formalization, implementation and validation. A state of the art about cortical deformations has been established in order to identify relevant parameters probably involved in the deformations. As a first step, 30 parameters have been identified and described following an ontological approach. They were formalized into a Unified Modeling Language (UML) class diagram. We implemented that model into a web-based application in order to fill a database. Two surgical cases have been studied at this moment. After having entered enough surgical cases for data mining purposes, we expect to identify the most relevant and influential parameters and to gain a better ability to understand the deformation phenomenon. This original approach is part of a global system aiming at quantifying and correcting anatomical deformations.

  10. A laser Doppler system for monitoring cerebral microcirculation: implementation and evaluation during neurosurgery.

    PubMed

    Rejmstad, Peter; Åkesson, Gustav; Åneman, Oscar; Wårdell, Karin

    2016-01-01

    The aim of this study was to adapt and evaluate laser Doppler perfusion monitoring (LDPM) together with custom-designed brain probes and software for continuous recording of cerebral microcirculation in patients undergoing neurosurgery. The LDPM system was used to record perfusion and backscattered light (TLI). These parameters were displayed together with the extracted heart rate (HR), pulsatility index (PI) and signal trends from adjustable time intervals. Technical evaluation was done on skin during thermal provocation. Clinical measurements were performed on ten patients undergoing brain tumour surgery. Data from 76 tissue sites were captured with a length varying between 10 s to 15 min. Statistical comparisons were done using Mann-Whitney tests. Grey and tumour tissue could be separated from white matter using the TLI signal (p < 0.05). The perfusion was significantly higher in grey and tumour tissue compared to white matter (p < 0.005). LDPM was successfully used as an intraoperative tool for monitoring local blood flow and additional parameters linked to cerebral microcirculation (perfusion, TLI, HR and PI) during tumour resection. The systems stability opens up for studies in the postoperative care of patients with, for example, traumatic brain injury or subarachnoid haemorrhage. PMID:26105147

  11. Pycnogenol® and its fractions influence the function of isolated heart in rats with experimental diabetes mellitus.

    PubMed

    Kralova, Eva; Jankyova, Stanislava; Mucaji, Pavel; Gresakova, Eva; Stankovicova, Tatiana

    2015-02-01

    The aim of this study was to test the effect of Pycnogenol(®) (PYC) mixture and its three fractions (buthanolic, water, ethyl acetate) on heart function in rats with experimental diabetes mellitus (DM) and compare their effects to the diabetic group. Their antioxidant activity "in vitro" was also determined. DM rats (streptozotocin over 3 consecutive days at a dose of 25 mg/kg of body weight) had increased systolic blood pressure, thicker left ventriculi wall (LV) and weaker myocardial contraction, prolonged QT interval in comparison to controls rats. In comparison to the diabetic group, PYC (20 mg/kg b.w./day) suppressed the influence of DM on the LV, improved contraction, increased coronary flow and displayed negative effect on electrical activity of hearts. The most effective of PYC's fractions was the water fraction. It improved biometric parameters and hemodynamic function of the DM hearts, enhanced shortening the QT interval, reduced the amount of dysrhythmias of the DM hearts and had the strongest antioxidant activity. In conclusion, DM damaged isolated rat heart function. Only the water fraction improved the function of the diabetic heart. The different results of three fractions and PYC on myocardial function may be caused by a various lipo- and hydro-philic action of the PYC components. PMID:25532475

  12. Why species matter: an experimental assessment of assumptions and predictive ability of two functional-group models.

    PubMed

    Fong, Caitlin R; Fong, Peggy

    2014-08-01

    Community ecologists use functional groups based on the rarely tested assumption that within-group responses to ecological processes are similar and thus members are functionally equivalent. However, recent research suggests that functional equivalency may break down with human impacts. We tested the equivalency assumption and model predictions of responses to simulated human alterations in nutrients and large herbivores for two models of coral reef algae, the Relative Dominance Model (RDM) and the Functional Group Model (FGM). Results of both mesocosm and field experiments using assembled communities were compared to model predictions, and within- and between-group variability were assessed. Both models' predictions of group response to herbivory matched experimental outcomes, but only the RDM predicted response to nutrients. However, within-group variability was dramatic, because the RDM grouped species with opposite responses to herbivory and the FGM grouped species with unique responses to nutrients. These heterogeneous responses resulted in loss of information and masked strong interactions between herbivory and nutrients that were not included in the models. As humans continue to impact major ecological processes in ecosystems globally, we postulate that functional-group models may need to be reformulated to account for shifting baselines. PMID:25230457

  13. Experimental demonstration of using divergence cost-function in SPGD algorithm for coherent beam combining with tip/tilt control.

    PubMed

    Geng, Chao; Luo, Wen; Tan, Yi; Liu, Hongmei; Mu, Jinbo; Li, Xinyang

    2013-10-21

    A novel approach of tip/tilt control by using divergence cost function in stochastic parallel gradient descent (SPGD) algorithm for coherent beam combining (CBC) is proposed and demonstrated experimentally in a seven-channel 2-W fiber amplifier array with both phase-locking and tip/tilt control, for the first time to our best knowledge. Compared with the conventional power-in-the-bucket (PIB) cost function for SPGD optimization, the tip/tilt control using divergence cost function ensures wider correction range, automatic switching control of program, and freedom of camera's intensity-saturation. Homemade piezoelectric-ring phase-modulator (PZT PM) and adaptive fiber-optics collimator (AFOC) are developed to correct piston- and tip/tilt-type aberrations, respectively. The PIB cost function is employed for phase-locking via maximization of SPGD optimization, while the divergence cost function is used for tip/tilt control via minimization. An average of 432-μrad of divergence metrics in open loop has decreased to 89-μrad when tip/tilt control implemented. In CBC, the power in the full width at half maximum (FWHM) of the main lobe increases by 32 times, and the phase residual error is less than λ/15. PMID:24150347

  14. Mesenchymal stem cells abrogate experimental asthma by altering dendritic cell function

    PubMed Central

    ZENG, SHAO-LIN; WANG, LI-HUI; LI, PING; WANG, WEI; YANG, JIONG

    2015-01-01

    Mesenchymal stem cells (MSCs) have been investigated in the treatment of numerous autoimmune diseases. However, the immune properties of MSCs on the development of asthma have remained to be fully elucidated. Airway dendritic cells (DCs) have an important role in the pathogenesis of allergic asthma, and disrupting their function may be a novel therapeutic approach. The present study used a mouse model of asthma to demonstrate that transplantation of MSCs suppressed features of asthma by targeting the function of lung myeloid DCs. MSCs suppressed the maturation and migration of lung DCs to the mediastinal lymph nodes, and thereby reducing the allergen-specific T helper type 2 (Th2) response in the nodes. In addition, MSC-treated DCs were less potent in activating naive and effector Th2 cells and the capacity of producing chemokine (C-C motif) ligand 17 (CCL17) and CCL22, which are chemokines attracting Th2 cells, to the airways was reduced. These results supported that MSCs may be used as a potential treatment for asthma. PMID:25936350

  15. [Effect of dietary protein on the function and morphology of diaphragm in rats with experimental emphysema].

    PubMed

    Zhao, Y; Shen, L

    2001-11-01

    The effects of dietary protein on the function and morphology of diaphragm of rats with emphysema were observed in 50 SD rats, 10 rats in each group. The emphysema in groups E(emphysema control), HP(emphysema with high protein diet) and LP(emphysema with low protein diet) was induced by intra-tracheal instillation of elastase (750 U/kg BW). The control rat (C1, C2) were instilled with normal saline. After 6 weeks of experiment, the total lung volume and the average area of alveolus was significantly increased in the group E compared with group C1 (P < 0.05) and the number of alveolus per unit area was also reduced obviously (P < 0.05). The average contractile force of diaphragm at a stimulus rate of 20 Hz expressed as a ratio of the maximal contractile force (F20/Fmax) was increased significantly in group E compared with group C (P < 0.01). The cross-sectional area of slow-twitch fibers increased significantly in group E. After 10 weeks of oral supplementation with 24% casein(HP) or 8% casein (LP) to the rats with emphysema, the contractility of the diaphragm in group LP was lower than that in the control group and the HP group. It was concluded that high protein diet might be beneficial to maintain the function of diaphragm in patients with emphysema. PMID:12561617

  16. Inhibition of LINGO-1 promotes functional recovery after experimental spinal cord demyelination.

    PubMed

    Zhang, Yongjie; Zhang, Yi Ping; Pepinsky, Blake; Huang, Guanrong; Shields, Lisa B E; Shields, Christopher B; Mi, Sha

    2015-04-01

    Blocking LINGO-1 has been shown to enhance remyelination in the rat lysolecithin-induced focal spinal cord demyelination model. We used transcranial magnetic motor-evoked potentials (tcMMEPs) to assess the effect of blocking LINGO-1 on recovery of axonal function in a mouse lysolecithin model at 1, 2 and 4weeks after injury. The role of LINGO-1 was assessed using LINGO-1 knockout (KO) mice and in wild-type mice after intraperitoneal administration of anti-LINGO-1 antagonist monoclonal antibody (mAb3B5). Response rates (at 2 and 4weeks) and amplitudes (at 4weeks) were significantly increased in LINGO-1 KO and mAb3B5-treated mice compared with matched controls. The latency of potentials at 4weeks was significantly shorter in mAb3B5-treated mice compared with controls. Lesion areas in LINGO-1 KO and mAb3B5-treated mice were reduced significantly compared with matched controls. The number of remyelinated axons within the lesions was increased and the G-ratios of the axons were decreased in both LINGO-1 KO and mAb3B5-treated mice compared with matched controls. These data provide morphometric and functional evidence of enhancement of remyelination associated with antagonism of LINGO-1. PMID:25681574

  17. Mesenchymal stem cells abrogate experimental asthma by altering dendritic cell function.

    PubMed

    Zeng, Shao-Lin; Wang, Li-Hui; Li, Ping; Wang, Wei; Yang, Jiong

    2015-08-01

    Mesenchymal stem cells (MSCs) have been investigated in the treatment of numerous autoimmune diseases. However, the immune properties of MSCs on the development of asthma have remained to be fully elucidated. Airway dendritic cells (DCs) have an important role in the pathogenesis of allergic asthma, and disrupting their function may be a novel therapeutic approach. The present study used a mouse model of asthma to demonstrate that transplantation of MSCs suppressed features of asthma by targeting the function of lung myeloid DCs. MSCs suppressed the maturation and migration of lung DCs to the mediastinal lymph nodes, and thereby reducing the allergen-specific T helper type 2 (Th2) response in the nodes. In addition, MSC-treated DCs were less potent in activating naive and effector Th2 cells and the capacity of producing chemokine (C-C motif) ligand 17 (CCL17) and CCL22, which are chemokines attracting Th2 cells, to the airways was reduced. These results supported that MSCs may be used as a potential treatment for asthma. PMID:25936350

  18. Male physical aggression as a function of alcohol intoxication and frustration: experimental results and methodological considerations.

    PubMed

    Gustafson, R

    1991-03-01

    Forty-five undergraduate students were assigned to either an Alcohol, a Placebo, or a Control group. The alcohol dose was 0.80 g of 100% alcohol/kg body weight. Subjects were informed that they could win a sum of money depending on the performance of a partner. They then supervised the partner over a series of trials on a visual scan test and could influence the partner by either giving an uncomfortable electric shock (aggressive alternative) or a comfortable vibration (nonaggressive alternative) at each incorrect response from the partner. Both alternatives were said to be equally instrumental in reaching the goal of winning the money and both could be varied in intensity on a 10-point scale and without limits in terms of duration. Aggression was measured as number of aggressive responses chosen, and in terms of intensity and duration. Nonaggression was measured in terms of intensity and duration. Intoxicated subjects did not increase their aggression but all groups chose significantly more nonaggressive responses and did so with higher intensity and duration. Frustration did not significantly affect these types of responding. Results are discussed in terms of methodological considerations and the importance of using realistic experimental paradigms is stressed. Also, theoretical implications are discussed. PMID:2058788

  19. Experimental Gestational Diabetes Mellitus Induces Blunted Vasoconstriction and Functional Changes in the Rat Aorta

    PubMed Central

    Tufiño, Cecilia; Villanueva-López, Cleva; Ibarra-Barajas, Maximiliano; Bracho-Valdés, Ismael; Bobadilla-Lugo, Rosa Amalia

    2014-01-01

    Diabetic conditions increase vascular reactivity to angiotensin II in several studies but there are scarce reports on cardiovascular effects of hypercaloric diet (HD) induced gestational diabetes mellitus (GDM), so the objective of this work was to determine the effects of HD induced GDM on vascular responses. Angiotensin II as well as phenylephrine induced vascular contraction was tested in isolated aorta rings with and without endothelium from rats fed for 7 weeks (4 before and 3 weeks during pregnancy) with standard (SD) or hypercaloric (HD) diet. Also, protein expression of AT1R, AT2R, COX-1, COX-2, NOS-1, and NOS-3 and plasma glucose, insulin, and angiotensin II levels were measured. GDM impaired vasoconstrictor response (P < 0.05 versus SD) in intact (e+) but not in endothelium-free (e−) vessels. Losartan reduced GDM but not SD e− vasoconstriction (P < 0.01 versus SD). AT1R, AT2R, and COX-1 and COX-2 protein expression were significantly increased in GDM vessels (P < 0.05 versus SD). Results suggest an increased participation of endothelium vasodilator mediators, probably prostaglandins, as well as of AT2 vasodilator receptors as a compensatory mechanism for vasoconstrictor changes generated by experimental GDM. Considering the short term of rat pregnancy findings can reflect early stage GDM adaptations. PMID:25610861

  20. Hydrogen-rich water improves neurological functional recovery in experimental autoimmune encephalomyelitis mice.

    PubMed

    Zhao, Ming; Liu, Ming-Dong; Pu, Ying-Yan; Wang, Dan; Xie, Yu; Xue, Gai-Ci; Jiang, Yong; Yang, Qian-Qian; Sun, Xue-Jun; Cao, Li

    2016-05-15

    Multiple sclerosis (MS) is a chronic autoimmune demyelinating disease of the central nervous system (CNS). The high costs, inconvenient administration, and side effects of current Food and Drug Administration (FDA)-approved drugs often lead to poor adherence to the long-term treatment of MS. Molecular hydrogen (H2) has been reported to exhibit anti-oxidant, anti-apoptotic, anti-inflammatory, anti-allergy, and anti-cancer effects. In the present study, we explored the prophylactic and therapeutic effects of hydrogen-rich water (HRW) on the progress of experimental autoimmune encephalomyelitis (EAE), the animal model for MS. We found that prophylactic administration of both 0.36mM and 0.89mM HRW was able to delay EAE onset and reduce maximum clinical scores. Moreover, 0.89mM HRW also reduced disease severity, CNS infiltration, and demyelination when administered after the onset of disease. Furthermore, HRW treatment prevented infiltration of CD4(+) T lymphocytes into the CNS and inhibited Th17 cell development without affecting Th1 cell populations. Because HRW is non-toxic, inexpensive, easily administered, and can readily cross the blood-brain barrier, our experiments suggest that HRW may have great potential in the treatment of MS. PMID:27138092

  1. Experimental assessment of the accuracy of predicting attenuation-function moduli in the LF and MF ranges

    NASA Astrophysics Data System (ADS)

    Pertel, M. I.; Pylaev, A. A.; Shteinberg, A. A.

    The present study examines the feasibility and accuracy of predicting attenuation-function moduli in the LF and MF ranges of the radio spectrum for the example of a portion of the European region of the USSR which is flat but complex in the geoelectric respect and heavily populated. The proposed method for calculating the wave-propagation parameters and for compiling maps of geoelectric sections of the underlying surface has been verified experimentally, and prediction accuracies of 1-1.5 dB and 1.5-4 dB were achieved in the LF and MF ranges, respectively.

  2. Experimental measurement of modulation transfer function of a retina-like sensor

    NASA Astrophysics Data System (ADS)

    Wang, Fan; Cao, Fengmei; Bai, Tingzhu; Cao, Nan; Liu, Changju; Deng, Guangping

    2014-11-01

    The retina-like sensor is a kind of anthropomorphic visual sensor. It plays an important role in both biological and machine vision due to its advantages of high resolution in the fovea, a wide field-of-view, and minimum pixel count. The space-variant property of the sensor makes it difficult to directly measure its modulation transfer function (MTF). The MTF of a retina-like sensor is measured with the bar-target pattern method. According to the pixel arrangement, the sensor is divided into rings and the MTF of each ring is measured using spoke targets with different periods. Comparison between the measured MTF and the theoretical MTF of the sensor showed that they coincide. The differences between them are also analyzed and discussed. The measured MTF helps to analyze the performance of an imaging system containing a retina-like sensor.

  3. Proton and deuteron induced reactions on natGa: Experimental and calculated excitation functions

    NASA Astrophysics Data System (ADS)

    Hermanne, A.; Adam-Rebeles, R.; Tárkányi, F.; Takács, S.; Ditrói, F.

    2015-09-01

    Cross-sections for reactions on natGa, induced by protons (up to 65 MeV) and deuterons (up to 50 MeV), producing γ-emitting radionuclides with half-lives longer than 1 h were measured in a stacked-foil irradiation using thin Ga-Ni alloy (70-30%) targets electroplated on Cu or Au backings. Excitation functions for generation of 68,69Ge, 66,67,68,72Ga and 65,69mZn on natGa are discussed, relative to the monitor reactions natAl(d,x)24,22Na, natAl(p,x)24,22Na, natCu(p,x)62Zn and natNi(p,x)57Ni. The results are compared to our earlier measurements, the scarce literature values and to the results of the code TALYS 1.6 (online database TENDL-2014).

  4. Experimental design and multiple response optimization. Using the desirability function in analytical methods development.

    PubMed

    Candioti, Luciana Vera; De Zan, María M; Cámara, María S; Goicoechea, Héctor C

    2014-06-01

    A review about the application of response surface methodology (RSM) when several responses have to be simultaneously optimized in the field of analytical methods development is presented. Several critical issues like response transformation, multiple response optimization and modeling with least squares and artificial neural networks are discussed. Most recent analytical applications are presented in the context of analytLaboratorio de Control de Calidad de Medicamentos (LCCM), Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, C.C. 242, S3000ZAA Santa Fe, ArgentinaLaboratorio de Control de Calidad de Medicamentos (LCCM), Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, C.C. 242, S3000ZAA Santa Fe, Argentinaical methods development, especially in multiple response optimization procedures using the desirability function. PMID:24767454

  5. Confronting QCD with the experimental hadronic spectral functions from tau decay

    SciTech Connect

    Dominguez, C. A.; Nasrallah, N. F.; Schilcher, K.

    2009-09-01

    The (nonstrange) vector and axial-vector spectral functions extracted from {tau} decay by the ALEPH Collaboration are confronted with QCD in the framework of a finite energy sum rule involving a polynomial kernel tuned to suppress the region beyond the kinematical end point where there is no longer data. This effectively allows for a QCD finite energy sum rule analysis to be performed beyond the region of the existing data. Results show excellent agreement between data and perturbative QCD in the remarkably wide energy range s=3-10 GeV{sup 2}, leaving room for a dimension d=4 vacuum condensate consistent with values in the literature. A hypothetical dimension d=2 term in the operator product expansion is found to be extremely small, consistent with zero. Fixed order and contour improved perturbation theory are used, with both leading to similar results within errors. Full consistency is found between vector and axial-vector channel results.

  6. Experimental evidence for friction-enhancing integumentary modifications of chameleons and associated functional and evolutionary implications.

    PubMed

    Khannoon, Eraqi R; Endlein, Thomas; Russell, Anthony P; Autumn, Kellar

    2014-01-22

    The striking morphological convergence of hair-like integumentary derivatives of lizards and arthropods (spiders and insects) demonstrates the importance of such features for enhancing purchase on the locomotor substrate. These pilose structures are responsible for the unique tractive abilities of these groups of animals, enabling them to move with seeming ease on overhanging and inverted surfaces, and to traverse inclined smooth substrates. Three groups of lizards are well known for bearing adhesion-promoting setae on their digits: geckos, anoles and skinks. Similar features are also found on the ventral subdigital and distal caudal skin of chameleons. These have only recently been described in any detail, and structurally and functionally are much less well understood than are the setae of geckos and anoles. The seta-like structures of chameleons are not branched (a characteristic of many geckos), nor do they terminate in spatulate tips (which is characteristic of geckos, anoles and skinks). They are densely packed and have attenuated blunt, globose tips or broad, blade-like shafts that are flattened for much of their length. Using a force transducer, we tested the hypothesis that these structures enhance friction and demonstrate that the pilose skin has a greater frictional coefficient than does the smooth skin of these animals. Our results are consistent with friction being generated as a result of side contact of the integumentary filaments. We discuss the evolutionary and functional implications of these seta-like structures in comparison with those typical of other lizard groups and with the properties of seta-mimicking synthetic structures. PMID:24285195

  7. Experimental evidence for friction-enhancing integumentary modifications of chameleons and associated functional and evolutionary implications

    PubMed Central

    Khannoon, Eraqi R.; Endlein, Thomas; Russell, Anthony P.; Autumn, Kellar

    2014-01-01

    The striking morphological convergence of hair-like integumentary derivatives of lizards and arthropods (spiders and insects) demonstrates the importance of such features for enhancing purchase on the locomotor substrate. These pilose structures are responsible for the unique tractive abilities of these groups of animals, enabling them to move with seeming ease on overhanging and inverted surfaces, and to traverse inclined smooth substrates. Three groups of lizards are well known for bearing adhesion-promoting setae on their digits: geckos, anoles and skinks. Similar features are also found on the ventral subdigital and distal caudal skin of chameleons. These have only recently been described in any detail, and structurally and functionally are much less well understood than are the setae of geckos and anoles. The seta-like structures of chameleons are not branched (a characteristic of many geckos), nor do they terminate in spatulate tips (which is characteristic of geckos, anoles and skinks). They are densely packed and have attenuated blunt, globose tips or broad, blade-like shafts that are flattened for much of their length. Using a force transducer, we tested the hypothesis that these structures enhance friction and demonstrate that the pilose skin has a greater frictional coefficient than does the smooth skin of these animals. Our results are consistent with friction being generated as a result of side contact of the integumentary filaments. We discuss the evolutionary and functional implications of these seta-like structures in comparison with those typical of other lizard groups and with the properties of seta-mimicking synthetic structures. PMID:24285195

  8. Impact of Cardiopulmonary Bypass on Respiratory Mucociliary Function in an Experimental Porcine Model

    PubMed Central

    Sánchez-Véliz, Rodrigo; Carmona, Maria José; Otsuki, Denise Aya; Freitas, Claudia; Benício, Anderson; Negri, Elnara Marcia; Malbouisson, Luiz Marcelo

    2015-01-01

    Background The impact of cardiac surgery using cardiopulmonary bypass (CPB) on the respiratory mucociliary function is unknown. This study evaluated the effects of CPB and interruption of mechanical ventilation on the respiratory mucociliary system. Methods Twenty-two pigs were randomly assigned to the control (n = 10) or CPB group (n = 12). After the induction of anesthesia, a tracheostomy was performed, and tracheal tissue samples were excised (T0) from both groups. All animals underwent thoracotomy. In the CPB group, an aorto-bicaval CPB was installed and maintained for 90 minutes. During the CPB, mechanical ventilation was interrupted, and the tracheal tube was disconnected. A second tracheal tissue sample was obtained 180 minutes after the tracheostomy (T180). Mucus samples were collected from the trachea using a bronchoscope at T0, T90 and T180. Ciliary beat frequency (CBF) and in situ mucociliary transport (MCT) were studied in ex vivo tracheal epithelium. Mucus viscosity (MV) was assessed using a cone-plate viscometer. Qualitative tracheal histological analysis was performed at T180 tissue samples. Results CBF decreased in the CPB group (13.1 ± 1.9 Hz vs. 11.1 ± 2.1 Hz, p < 0.05) but not in the control group (13.1 ± 1 Hz vs. 13 ± 2.9 Hz). At T90, viscosity was increased in the CPB group compared to the control (p < 0.05). No significant differences were observed in in situ MCT. Tracheal histology in the CPB group showed areas of ciliated epithelium loss, submucosal edema and infiltration of inflammatory cells. Conclusion CPB acutely contributed to alterations in tracheal mucocilliary function. PMID:26288020

  9. Catechin averts experimental diabetes mellitus-induced vascular endothelial structural and functional abnormalities.

    PubMed

    Bhardwaj, Pooja; Khanna, Deepa; Balakumar, Pitchai

    2014-03-01

    Diabetes mellitus is associated with an induction of vascular endothelial dysfunction (VED), an initial event that could lead to the pathogenesis of atherosclerosis and hypertension. Previous studies showed that catechin, a key component of green tea, possesses vascular beneficial effects. We investigated the effect of catechin hydrate in diabetes mellitus-induced experimental vascular endothelial abnormalities (VEA). Streptozotocin (50 mg/kg, i.p., once) administration to rats produced diabetes mellitus, which subsequently induced VEA in 8 weeks by markedly attenuating acetylcholine-induced endothelium-dependent relaxation in the isolated aortic ring preparation, decreasing aortic and serum nitrite/nitrate concentrations and impairing aortic endothelial integrity. These abnormalities in diabetic rats were accompanied with elevated aortic superoxide anion generation and serum lipid peroxidation in addition to hyperglycemia. Catechin hydrate treatment (50 mg/kg/day p.o., 3 weeks) markedly prevented diabetes mellitus-induced VEA and vascular oxidative stress. Intriguingly, in vitro incubation of L-NAME (100 μM), an inhibitor of nitric oxide synthase, or Wortmannin (100 nM), a selective inhibitor of phosphatidylinositol 3-kinase (PI3K), markedly prevented catechin hydrate-induced improvement in acetylcholine-provoked endothelium-dependent relaxation in the diabetic rat aorta. Moreover, catechin hydrate treatment considerably reduced the elevated level of serum glucose in diabetic rats. In conclusion, catechin hydrate treatment prevents diabetes mellitus-induced VED through the activation of endothelial PI3K signal and subsequent activation of eNOS and generation of nitric oxide. In addition, reduction in high glucose, vascular oxidative stress, and lipid peroxidation might additionally contribute to catechin hydrate-associated prevention of diabetic VEA. PMID:24048981

  10. Protective effect of theophylline on renal functions in experimental pneumoperitoneum model.

    PubMed

    Ozturk, Sefa Alperen; Ceylan, Cavit; Serel, Tekin Ahmet; Doluoglu, Omer Gokhan; Soyupek, Arap Sedat; Guzel, Ahmet; Özorak, Alper; Uz, Efkan; Savas, Hasan Basri; Baspinar, Sirin

    2015-07-01

    Our objective in this experimental study is to research the effect of the intra-abdominal pressure which rises following pneumoperitoneum and whether Theophylline has a possible protective activity on this situation. In our study, 24 Wistar Albino rats were used. Rats were divided into two groups. The first group was set for only pneumoperitoneum model. The second group was given 15 mg/kg of Theophylline intraperitoneally before setting pneumoperitoneum model. Then urea, creatinine, cystatin-C, tissue and serum total antioxidant capacity, total oxidant capacity and oxidative stress index in two groups were measured and compared with each other. Apoptosis and histopathological conditions in the renal tissues were examined. The differences between the groups were analyzed with the Mann-Whitney U test. Results were considered significant at p < 0.05. No statistically significant difference was determined between tissue and serum averages in two groups in terms of TAS, TOS and OSI values (p > 0.05). The mean value of urea were similar in pneumoperitoneum and pneumoperitoneum + theophylline groups (p = 0.12). The mean cystatin-C value was 2.2 ± 0.3 µg/mL in pneumoperitoneum, 1.74 ± 0.33 µg/mL in pneumoperitoneum + theophylline (p = 0.002). According to our study, lower cystatin-C levels in the group, where Theophylline was given, are suggestive of lower renal injury in this group. However, this opinion is interrogated as there is no difference in terms of tissue and serum TAS, TOS, OSI and urea values between the groups. PMID:25959022

  11. Elevation of serum sphingosine-1-phosphate attenuates impaired cardiac function in experimental sepsis

    PubMed Central

    Coldewey, Sina M.; Benetti, Elisa; Collino, Massimo; Pfeilschifter, Josef; Sponholz, Christoph; Bauer, Michael; Huwiler, Andrea; Thiemermann, Christoph

    2016-01-01

    Serum levels of the lipid mediator sphingosine-1-phosphate (S1P) are reduced in septic patients and are inversely associated with disease severity. We show that serum S1P is reduced in human sepsis and in murine models of sepsis. We then investigated whether pharmacological or genetic approaches that alter serum S1P may attenuate cardiac dysfunction and whether S1P signaling might serve as a novel theragnostic tool in sepsis. Mice were challenged with lipopolysaccharide and peptidoglycan (LPS/PepG). LPS/PepG resulted in an impaired systolic contractility and reduced serum S1P. Administration of the immunomodulator FTY720 increased serum S1P, improved impaired systolic contractility and activated the phosphoinositide 3-kinase (PI3K)-pathway in the heart. Cardioprotective effects of FTY720 were abolished following administration of a S1P receptor 2 (S1P2) antagonist or a PI3K inhibitor. Sphingosine kinase-2 deficient mice had higher endogenous S1P levels and the LPS/PepG-induced impaired systolic contractility was attenuated in comparison with wild-type mice. Cardioprotective effects of FTY720 were confirmed in polymicrobial sepsis. We show here for the first time that the impaired left ventricular systolic contractility in experimental sepsis is attenuated by FTY720. Mechanistically, our results indicate that activation of S1P2 by increased serum S1P and the subsequent activation of the PI3K-Akt survival pathway significantly contributes to the observed cardioprotective effect of FTY720. PMID:27277195

  12. Elevation of serum sphingosine-1-phosphate attenuates impaired cardiac function in experimental sepsis.

    PubMed

    Coldewey, Sina M; Benetti, Elisa; Collino, Massimo; Pfeilschifter, Josef; Sponholz, Christoph; Bauer, Michael; Huwiler, Andrea; Thiemermann, Christoph

    2016-01-01

    Serum levels of the lipid mediator sphingosine-1-phosphate (S1P) are reduced in septic patients and are inversely associated with disease severity. We show that serum S1P is reduced in human sepsis and in murine models of sepsis. We then investigated whether pharmacological or genetic approaches that alter serum S1P may attenuate cardiac dysfunction and whether S1P signaling might serve as a novel theragnostic tool in sepsis. Mice were challenged with lipopolysaccharide and peptidoglycan (LPS/PepG). LPS/PepG resulted in an impaired systolic contractility and reduced serum S1P. Administration of the immunomodulator FTY720 increased serum S1P, improved impaired systolic contractility and activated the phosphoinositide 3-kinase (PI3K)-pathway in the heart. Cardioprotective effects of FTY720 were abolished following administration of a S1P receptor 2 (S1P2) antagonist or a PI3K inhibitor. Sphingosine kinase-2 deficient mice had higher endogenous S1P levels and the LPS/PepG-induced impaired systolic contractility was attenuated in comparison with wild-type mice. Cardioprotective effects of FTY720 were confirmed in polymicrobial sepsis. We show here for the first time that the impaired left ventricular systolic contractility in experimental sepsis is attenuated by FTY720. Mechanistically, our results indicate that activation of S1P2 by increased serum S1P and the subsequent activation of the PI3K-Akt survival pathway significantly contributes to the observed cardioprotective effect of FTY720. PMID:27277195

  13. An experimental study of permeability development as a function of crystal-free melt viscosity

    NASA Astrophysics Data System (ADS)

    Lindoo, A. N.; Larsen, J. F.

    2013-12-01

    The efficiency of volatile exsolution and degassing from an ascending magma influences eruption dynamics. We performed single-step decompression experiments using externally heated TZM alloy cold seal pressure vessels to investigate porosity-permeability relationships as a function of crystal-free melt viscosity. The experiments employed natural, finely powdered rhyolite (76 % SiO2), rhyodacite (70 % SiO2), K-phonolite (55 % SiO2), and basaltic andesite (54 % SiO2) starting compositions, with estimated viscosities varying between ~106-103 Pa s. We first held the experiments at water-saturated conditions of 900 (rhyolite, rhyodacite, and phonolite) and 1025°C (basaltic andesite) and 150 MPa for 2-72 hours. We decompressed the experiments isothermally to final pressures of 125 to 25 MPa at 1-5 MPa/s and quenched after holding for 0.25-60 minutes at the final pressure. After removing the run products from the capsules, we measured porosity using image processing methods and permeability using a gas permeameter. We employed the Forchheimer equation to estimate Darcian (viscous) and inertial permeabilities of each experiment. All experiments are impermeable below a critical porosity that appears to vary between the different melt compositions. For rhyolite samples, the permeability increases from 10-14 to 10-13 m2 at 63 - 80 vol. %, below which samples are impermeable. Rhyodacite is impermeable until the experiments reach ~67 vol. % porosity, at which the samples have viscous permeability of 10-12.3 m2; higher than the rhyolite at similar porosity. K-rich phonolite reaches viscous permeability of 10-14.5 m2 at 55 vol. % porosity. Basaltic andesite samples remain impermeable to pressures as low as 50 MPa. Our preliminary results indicate that the critical porosity at which magmas become permeable and degas during magma ascent may decrease as a function of decreasing melt viscosity. However, further experiments on the phonolite and basaltic andesite compositions are

  14. Exercise prevents the effects of experimental arthritis on the metabolism and function of immune cells.

    PubMed

    Navarro, Francisco; Bacurau, Aline V N; Almeida, Sandro S; Barros, Carlos C; Moraes, Milton R; Pesquero, Jorge L; Ribeiro, Sandra M L; Araújo, Ronaldo C; Costa Rosa, Luis F B P; Bacurau, Reury F P

    2010-06-01

    Active lymphocytes (LY) and macrophages (MPhi) are involved in the pathophysiology of rheumatoid arthritis (RA). Due to its anti-inflammatory effect, physical exercise may be beneficial in RA by acting on the immune system (IS). Thus, female Wistar rats with type II collagen-induced arthritis (CIA) were submitted to swimming training (6 weeks, 5 days/week, 60 min/day) and some biochemical and immune parameters, such as the metabolism of glucose and glutamine and function of LY and MPhi, were evaluated. In addition, plasma levels of some hormones and of interleukin-2 (IL-2) were also determined. Results demonstrate that CIA increased lymphocyte proliferation (1.9- and 1.7-fold, respectively, in response to concanavalin A (ConA) and lipopolysaccharide (LPS)), as well as macrophage H(2)O(2) production (1.6-fold), in comparison to control. Exercise training prevented the activation of immune cells, induced by CIA, and established a pattern of substrate utilization similar to that described as normal for these cells. Exercise also promoted an elevation of plasma levels of corticosterone (22.2%), progesterone (1.7-fold) and IL-2 (2.6-fold). Our data suggest that chronic exercise is able to counterbalance the effects of CIA on cells of the IS, reinforcing the proposal that the benefits of exercise may not be restricted to aerobic capacity and/or strength improvement. PMID:20517889

  15. Experimental Modification of Rat Pituitary Growth Hormone Cell Function During and After Spaceflight

    NASA Technical Reports Server (NTRS)

    Hymer, W. C.; Salada, T.; Nye, P.; Grossman, E. J.; Lane, P. K.; Grindeland, R. E.

    1996-01-01

    Space-flown rats show a number of flight-induced changes in the structure and function of pituitary Growth Hormone (GH) cells after in vitro postflight testing. To evaluate the possible effects of microgravity on GH cells themselves, freshly dispersed rat anterior pituitary gland cells were seeded into vials containing serum +/- 1 micron HydroCortisone (HC) before flight. Five different cell preparations were used: the entire mixed-cell population of various hormone-producing cell types, cells of density less than 1.071 g/sq cm (band 1), cells of density greater than 1.071 g/sq cm (band 2), and cells prepared from either the dorsal or ventral part of the gland. Relative to ground control samples, bioactive GH released from dense cells during flight was reduced in HC-free medium but was increased in HC-containing medium. Band I and mixed cells usually showed opposite HC-dependent responses. Release of bioactive GH from ventral flight cells was lower; postflight responses to GH-releasing hormone challenge were reduced, and the cytoplasmic area occupied by GH in the dense cells was greater. Collectively, the data show that the chemistry and cellular makeup of the culture system modifies the response of GH cells to microgravity. As such, these cells offer a system to identify gravisensing mechanisms in secretory cells in future microgravity research.

  16. Experimental and density functional theory study of Raman and SERS spectra of 5-amino-2-mercaptobenzimidazole

    NASA Astrophysics Data System (ADS)

    Chen, Yufeng; Yang, Jin; Li, Zonglong; Li, Ran; Ruan, Weidong; Zhuang, Zhiping; Zhao, Bing

    2016-01-01

    Raman spectroscopy, surface-enhanced Raman spectroscopy (SERS) and density functional theory (DFT) simulations were employed to study 5-amino-2-mercaptobenzimidazole (5-A-2MBI) molecules. Ag colloids were used as SERS substrates which were prepared by using hydroxylamine hydrochloride as reducing agent. Raman vibration modes and SERS characteristic peaks of 5-A-2MBI were assigned with the aid of DFT calculations. The molecular electrostatic potential (MEP) of 5-A-2MBI was used to discuss the possible adsorption behavior of 5-A-2MBI on Ag colloids. The spectral analysis showed that 5-A-2MBI molecules were slightly titled via the sulfur atoms adhering to the surfaces of Ag substrates. The obtained SERS spectral intensity decreased when lowering the 5-A-2MBI concentrations. A final detection limit on the concentration of 5 × 10- 7 mol · L- 1 was gained. SERS proved to be a simple, fast and reliable method for the detection and characterization of 5-A-2MBI molecules.

  17. Gaussian functional regression for output prediction: Model assimilation and experimental design

    NASA Astrophysics Data System (ADS)

    Nguyen, N. C.; Peraire, J.

    2016-03-01

    In this paper, we introduce a Gaussian functional regression (GFR) technique that integrates multi-fidelity models with model reduction to efficiently predict the input-output relationship of a high-fidelity model. The GFR method combines the high-fidelity model with a low-fidelity model to provide an estimate of the output of the high-fidelity model in the form of a posterior distribution that can characterize uncertainty in the prediction. A reduced basis approximation is constructed upon the low-fidelity model and incorporated into the GFR method to yield an inexpensive posterior distribution of the output estimate. As this posterior distribution depends crucially on a set of training inputs at which the high-fidelity models are simulated, we develop a greedy sampling algorithm to select the training inputs. Our approach results in an output prediction model that inherits the fidelity of the high-fidelity model and has the computational complexity of the reduced basis approximation. Numerical results are presented to demonstrate the proposed approach.

  18. Experimentally induced hyperthyroidism influences oxidant and antioxidant status and impairs male gonadal functions in adult rats.

    PubMed

    Asker, M E; Hassan, W A; El-Kashlan, A M

    2015-08-01

    The objective of the present experiment was to study the effect of hyperthyroidism on male gonadal functions and oxidant/antioxidant biomarkers in testis of adult rats. Induction of hyperthyroidism by L-thyroxine (L-T4, 300 μg kg(-1) body weight) treatment once daily for 3 or 8 weeks caused a decrease in body weight gain as well as in absolute genital sex organs weight. The epididymal sperm counts and their motility were significantly decreased in a time-dependent manner following L-T4 treatment. Significant decline in serum levels of luteinising hormone, follicle stimulating hormone and testosterone along with significant increase in serum estradiol level was observed in hyperthyroid rats compared with euthyroid ones. Significant increase in malondialdehyde and nitric oxide concentration associated with significant decrease in superoxide dismutase and catalase activity was also noticed following hyperthyroidism induction. Both reduced glutathione content and glutathione peroxidase activity were increased in hyperthyroid rats compared with control rats. Marked histopathological alterations were observed in testicular section of hyperthyroid rats. These results provide evidence that hypermetabolic state induced by excess level of thyroid hormones may be a causative factor for the impairment of testicular physiology as a consequence of oxidative stress. PMID:25220112

  19. Metabolite Profiles Correlate Closely with Neurobehavioral Function in Experimental Spinal Cord Injury in Rats

    PubMed Central

    Fujieda, Yusuke; Ueno, Shinya; Ogino, Ryoko; Kuroda, Mariko; Jönsson, Thomas J.; Guo, Lining; Bamba, Takeshi; Fukusaki, Eiichiro

    2012-01-01

    Traumatic spinal cord injury (SCI) results in direct physical damage and the generation of local factors contributing to secondary pathogenesis. Untargeted metabolomic profiling was used to uncover metabolic changes and to identify relationships between metabolites and neurobehavioral functions in the spinal cord after injury in rats. In the early metabolic phase, neuronal signaling, stress, and inflammation-associated metabolites were strongly altered. A dynamic inflammatory response consisting of elevated levels of prostaglandin E2 and palmitoyl ethanolamide as well as pro- and anti-inflammatory polyunsaturated fatty acids was observed. N-acetyl-aspartyl-glutamate (NAAG) and N-acetyl-aspartate (NAA) were significantly decreased possibly reflecting neuronal cell death. A second metabolic phase was also seen, consistent with membrane remodeling and antioxidant defense response. These metabolomic changes were consistent with the pathology and progression of SCI. Several metabolites, including NAA, NAAG, and the ω-3 fatty acids docosapentaenoate and docosahexaenoate correlated greatly with the established Basso, Beattie and Bresnahan locomotive score (BBB score). Our findings suggest the possibility of a biochemical basis for BBB score and illustrate that metabolites may correlate with neurobehavior. In particular the NAA level in the spinal cord might provide a meaningful biomarker that could help to determine the degree of injury severity and prognosticate neurologic recovery. PMID:22912814

  20. Techniques for estimating the unknown functions of incomplete experimental spectral and correlation response matrices

    NASA Astrophysics Data System (ADS)

    Antunes, Jose; Borsoi, Laurent; Delaune, Xavier; Piteau, Philippe

    2016-02-01

    In this paper, we propose analytical and numerical straightforward approximate methods to estimate the unknown terms of incomplete spectral or correlation matrices, when the cross-spectra or cross-correlations available from multiple measurements do not cover all pairs of transducer locations. The proposed techniques may be applied whenever the available data includes the auto-spectra at all measurement locations, as well as selected cross-spectra which implicates all measurement locations. The suggested methods can also be used for checking the consistency between the spectral or correlation functions pertaining to measurement matrices, in cases of suspicious data. After presenting the proposed spectral estimation formulations, we discuss their merits and limitations. Then we illustrate their use on a realistic simulation of a multi-supported tube subjected to turbulence excitation from cross-flow. Finally, we show the effectiveness of the proposed techniques by extracting the modal responses of the simulated flow-excited tube, using the SOBI (Second Order Blind Identification) method, from an incomplete response matrix 1

  1. Metabolite profiles correlate closely with neurobehavioral function in experimental spinal cord injury in rats.

    PubMed

    Fujieda, Yusuke; Ueno, Shinya; Ogino, Ryoko; Kuroda, Mariko; Jönsson, Thomas J; Guo, Lining; Bamba, Takeshi; Fukusaki, Eiichiro

    2012-01-01

    Traumatic spinal cord injury (SCI) results in direct physical damage and the generation of local factors contributing to secondary pathogenesis. Untargeted metabolomic profiling was used to uncover metabolic changes and to identify relationships between metabolites and neurobehavioral functions in the spinal cord after injury in rats. In the early metabolic phase, neuronal signaling, stress, and inflammation-associated metabolites were strongly altered. A dynamic inflammatory response consisting of elevated levels of prostaglandin E2 and palmitoyl ethanolamide as well as pro- and anti-inflammatory polyunsaturated fatty acids was observed. N-acetyl-aspartyl-glutamate (NAAG) and N-acetyl-aspartate (NAA) were significantly decreased possibly reflecting neuronal cell death. A second metabolic phase was also seen, consistent with membrane remodeling and antioxidant defense response. These metabolomic changes were consistent with the pathology and progression of SCI. Several metabolites, including NAA, NAAG, and the ω-3 fatty acids docosapentaenoate and docosahexaenoate correlated greatly with the established Basso, Beattie and Bresnahan locomotive score (BBB score). Our findings suggest the possibility of a biochemical basis for BBB score and illustrate that metabolites may correlate with neurobehavior. In particular the NAA level in the spinal cord might provide a meaningful biomarker that could help to determine the degree of injury severity and prognosticate neurologic recovery. PMID:22912814

  2. An experimental and density functional study on conformational and spectroscopic analysis of 5-methoxyindole-2-carboxylic acid.

    PubMed

    Cinar, Mehmet; Karabacak, Mehmet; Asiri, Abdullah M

    2015-02-25

    In this article, a brief conformational and spectroscopic characterization of 5-methoxyindole-2-carboxylic acid (5-MeOICA) via experimental techniques and applications of quantum chemical methods is presented. The conformational analysis of the studied molecule was determined theoretically using density functional computations for ground state, and compared with previously reported experimental findings. The vibrational transitions were examined by measured FT-IR and FT-Raman spectroscopic data, and also results obtained from B3LYP and CAM-B3LYP functionals in combination with 6-311++G(d,p) basis set. The recorded proton and carbon NMR spectra in DMSO solution were analyzed to obtain the exact conformation. Due to intermolecular hydrogen bondings, NMR calculations were performed for the dimeric form of 5-MeOICA and so chemical shifts of those protons were predicted more accurately. Finally, electronic properties of steady compound were identified by a comparative study of UV absorption spectra in ethanol and water solution and TD-DFT calculations. PMID:25255480

  3. Alterations in functional connectivity of resting state networks during experimental endotoxemia - An exploratory study in healthy men.

    PubMed

    Labrenz, Franziska; Wrede, Karsten; Forsting, Michael; Engler, Harald; Schedlowski, Manfred; Elsenbruch, Sigrid; Benson, Sven

    2016-05-01

    Systemic inflammation impairs mood and cognitive functions, and seems to be involved in the pathophysiology of psychiatric disorders. Functional magnetic resonance imaging (fMRI) studies revealed altered task-related blood-oxygen-level-dependent (BOLD) responses during experimental endotoxemia, but little is known about effects of systemic inflammation on resting-state activity of the brain. Thus, we conducted a randomized, placebo-controlled study in healthy men receiving an intravenous injection of either low-dose (0.4ng/kg) lipopolysaccharide (LPS) (N=20) or placebo (N=25). Resting state activity was measured at baseline and 3.5h post-injection. Based on a two (condition)×two (group) design, we used multi-subject independent component analysis (ICA) to decompose and estimate functional connectivity within resting-state networks (RSNs). Seed-based analyses were applied to investigate the effect of LPS on the functional coupling for a priori-defined regions-of-interest (ROIs). ICA analyses identified 13 out of 35 components displaying common RSNs. Seed based analysis revealed greater functional connectivity between the left thalamus and the cerebellum after LPS compared to placebo administration, while the functional coupling between seeds within the amygdala, insula, and cingulate cortex and various brain regions including parieto-frontal networks was significantly reduced. Within the LPS group, endotoxin-induced increases in Interleukin (IL)-6 were significantly associated with resting-state connectivity between the left thalamus and left precuneus as well as the right posterior cingulate cortex. In summary, this exploratory study provides first evidence that systemic inflammation affects the coupling and regulation of multiple networks within the human brain at rest. PMID:26597151

  4. Different Assembly Processes Drive Shifts in Species and Functional Composition in Experimental Grasslands Varying in Sown Diversity and Community History

    PubMed Central

    Roscher, Christiane; Schumacher, Jens; Gerighausen, Uta; Schmid, Bernhard

    2014-01-01

    Background The prevalence of different biotic processes (limiting similarity, weaker competitor exclusion) and historical contingency due to priority effects are in the focus of ongoing discussions about community assembly and non-random functional trait distributions. Methodology/Principal Findings We experimentally manipulated assembly history in a grassland biodiversity experiment (Jena Experiment) by applying two factorially crossed split-plot treatments to all communities: (i) duration of weeding (never weeded since sowing or cessation of weeding after 3 or 6 years); (ii) seed addition (control vs. seed addition 4 years after sowing). Spontaneous colonization of new species in the control treatment without seed addition increased realized species richness and functional richness (FRic), indicating continuously denser packing of niches. Seed addition resulted in forced colonization and increased realized species richness, FRic, functional evenness (FEve) and functional divergence (FDiv), i.e. higher abundances of species with extreme trait values. Furthermore, the colonization of new species led to a decline in FEve through time, suggesting that weaker competitors were reduced in abundance or excluded. Communities with higher initial species richness or with longer time since cessation of weeding were more restricted in the entry of new species and showed smaller increases in FRic after seed addition than other communities. The two assembly-history treatments caused a divergence of species compositions within communities originally established with the same species. Communities originally established with different species converged in species richness and functional trait composition over time, but remained more distinct in species composition. Conclusions/Significance Contrasting biotic processes (limiting similarity, weaker competitor exclusion) increase functional convergence between communities initially established with different species. Historical

  5. Experimental Study of the Convergence of Two-Point Cross-Correlation Toward the Green's Function

    NASA Astrophysics Data System (ADS)

    Gouedard, P.; Roux, P.; Campillo, M.; Verdel, A.; Campman, X.

    2007-12-01

    It has been shown theoretically by several authors that cross-correlation of the seismic motion recorded at two points could yield the Green's Function (GF) between these points. Convergence of cross-correlations toward the GF depends on sources positions and/or the nature of the wavefield. Direct waves from an even distribution of sources can be used to retrieve the GF. On the other hand, in an inhomogeneous medium, recording the diffuse field (coda) is theoretically sufficient to retrieve the GF whatever the sources distribution is. Since none of these two conditions (even distribution of sources or a perfectly diffuse field) is satisfied in practice, the question of convergence toward the GF has to be investigated with real data. A 3D exploration survey with sources and receivers on a dense grid offers such an opportunity. We used a high- resolution survey recorded by Petroleum Development Oman in North Oman. The data have been obtained in a 1x1~km area covered with 1600 geophones located on a 25x25~m-cell grid. Records are 4-seconds long. A unique feature of this survey is that vibrators (working in the [8-120~Hz] frequency band), were located on a similar grid shifted with respect to the receiver grid by half a cell (12.5~m) in both directions. This allows us to compare estimated GF's with measured direct waves (GF's) between the geophones. The shallow subsurface is highly heterogeneous and records include seismic coda. From this dataset, we selected two receiver locations (Ra and Rb) distant from d=158~m. We used both different sets of source locations and time windows to compute the cross-correlation between these two receivers. Then we compared the derivatives of correlation functions with the actual GF measured in Rb (resp.~Ra) for a source close to Ra (resp.~Rb). By doing so, we show the actual influence of source locations and scattering (governed by the records' selected time window) on the Signal-to-Noise Ratio (SNR) of the reconstructed GF. When using

  6. Using experimental manipulation to assess the roles of leaf litter in the functioning of forest ecosystems.

    PubMed

    Sayer, Emma J

    2006-02-01

    The widespread use of forest litter as animal bedding in central Europe for many centuries gave rise to the first litter manipulation studies, and their results demonstrated that litter and its decomposition are a vital part of ecosystem function. Litter plays two major roles in forest ecosystems: firstly, litterfall is an inherent part of nutrient and carbon cycling, and secondly, litter forms a protective layer on the soil surface that also regulates microclimatic conditions. By reviewing 152 years of litter manipulation experiments, I show that the effects of manipulating litter stem from changes in one, or both, of these two functions, and interactions between the variables influenced by the accumulation of litter can result in feedback mechanisms that may intensify treatment effects or mask responses, making the interpretation of results difficult.Long-term litter removal increased soil bulk density, overland flow, erosion, and temperature fluctuations and upset the soil water balance, causing lower soil water content during dry periods. Soil pH increased or decreased in response to manipulation treatments depending on forest type and initial soil pH, but it is unclear why there was no uniform response. Long-term litter harvesting severely depleted the forests of nutrients. Decreases in the concentrations of available P, Ca, Mg, and K in the soil occurred after only three to five years. The decline in soil N occurred over longer periods of time, and the relative loss was greater in soils with high initial nitrogen concentration. Tree growth declined with long-term litter removal, probably due to lower nutrient availability. Litter manipulation also added or removed large amounts of carbon thereby affecting microbial communities and altering soil respiration rates. Litter manipulation experiments have shown that litter cover acts as a physical barrier to the shoot emergence of small-seeded species; further, the microclimate maintained by the litter layer may be

  7. Functioning of a Shallow-Water Sediment System during Experimental Warming and Nutrient Enrichment

    PubMed Central

    Alsterberg, Christian; Sundbäck, Kristina; Hulth, Stefan

    2012-01-01

    Effects of warming and nutrient enrichment on intact unvegetated shallow-water sediment were investigated for 5 weeks in the autumn under simulated natural field conditions, with a main focus on trophic state and benthic nitrogen cycling. In a flow-through system, sediment was exposed to either seawater at ambient temperature or seawater heated 4°C above ambient, with either natural or nutrient enriched water. Sediment–water fluxes of oxygen and inorganic nutrients, nitrogen mineralization, and denitrification were measured. Warming resulted in an earlier shift to net heterotrophy due to increased community respiration; primary production was not affected by temperature but (slightly) by nutrient enrichment. The heterotrophic state was, however, not further strengthened by warming, but was rather weakened, probably because increased mineralization induced a shortage of labile organic matter. Climate-related warming of seawater during autumn could therefore, in contrast to previous predictions, induce shorter but more intensive heterotrophic periods in shallow-water sediments, followed by longer autotrophic periods. Increased nitrogen mineralization and subsequent effluxes of ammonium during warming suggested a preferential response of organisms driving nitrogen mineralization when compared to sinks of ammonium such as nitrification and algal assimilation. Warming and nutrient enrichment resulted in non-additive effects on nitrogen mineralization and denitrification (synergism), as well as on benthic fluxes of phosphate (antagonism). The mode of interaction appears to be related to the trophic level of the organisms that are the main drivers of the affected processes. Despite the weak response of benthic microalgae to both warming and nutrient enrichment, the assimilation of nitrogen by microalgae was similar in magnitude to rates of nitrogen mineralization. This implies a sustained filter function and retention capacity of nutrients by the sediment. PMID

  8. Functioning of a shallow-water sediment system during experimental warming and nutrient enrichment.

    PubMed

    Alsterberg, Christian; Sundbäck, Kristina; Hulth, Stefan

    2012-01-01

    Effects of warming and nutrient enrichment on intact unvegetated shallow-water sediment were investigated for 5 weeks in the autumn under simulated natural field conditions, with a main focus on trophic state and benthic nitrogen cycling. In a flow-through system, sediment was exposed to either seawater at ambient temperature or seawater heated 4°C above ambient, with either natural or nutrient enriched water. Sediment-water fluxes of oxygen and inorganic nutrients, nitrogen mineralization, and denitrification were measured. Warming resulted in an earlier shift to net heterotrophy due to increased community respiration; primary production was not affected by temperature but (slightly) by nutrient enrichment. The heterotrophic state was, however, not further strengthened by warming, but was rather weakened, probably because increased mineralization induced a shortage of labile organic matter. Climate-related warming of seawater during autumn could therefore, in contrast to previous predictions, induce shorter but more intensive heterotrophic periods in shallow-water sediments, followed by longer autotrophic periods. Increased nitrogen mineralization and subsequent effluxes of ammonium during warming suggested a preferential response of organisms driving nitrogen mineralization when compared to sinks of ammonium such as nitrification and algal assimilation. Warming and nutrient enrichment resulted in non-additive effects on nitrogen mineralization and denitrification (synergism), as well as on benthic fluxes of phosphate (antagonism). The mode of interaction appears to be related to the trophic level of the organisms that are the main drivers of the affected processes. Despite the weak response of benthic microalgae to both warming and nutrient enrichment, the assimilation of nitrogen by microalgae was similar in magnitude to rates of nitrogen mineralization. This implies a sustained filter function and retention capacity of nutrients by the sediment. PMID:23240032

  9. Cortical reorganization after experimental traumatic brain injury: a functional autoradiography study.

    PubMed

    Harris, Neil G; Chen, Szu-Fu; Pickard, John D

    2013-07-01

    Cortical sensorimotor (SM) maps are a useful readout for providing a global view of the underlying status of evoked brain function, as well as a gross overview of ongoing mechanisms of plasticity. Recent evidence in the rat controlled cortical impact (CCI) injury model shows that the ipsilesional (injured) hemisphere is temporarily permissive for axon sprouting. This would predict that size and spatial alterations in cortical maps may occur much earlier than previously tested and that they might be useful as potential markers of the postinjury plasticity period as well as indicators of outcome. We investigated the evolution of changes in brain activation evoked by affected hindlimb electrical stimulation at 4, 7, and 30 days following CCI or sham injury over the hindlimb cortical region of adult rats. [(14)C]-iodoantipyrine autoradiography was used to quantitatively examine the local cerebral blood flow changes in response to hindlimb stimulation as a marker for neuronal activity. The results show that although ipsilesional hindlimb SM activity was persistently depressed from 4 days, additional novel regions of ipsilesional activity appeared concurrently within SM barrel and S2 regions as well as posterior auditory cortex. Simultaneously with this was the appearance of evoked activity within the intact, contralesional cortex that was maximal at 4 and 7 days, compared to stimulated sham-injured rats, where activation was solely unilateral. By 30 days, however, contralesional activation had greatly subsided and existing ipsilesional activity was enhanced within the same novel cortical regions that were identified acutely. These data indicate that significant reorganization of the cortical SM maps occurs after injury that evolves with a particular postinjury time course. We discuss these data in terms of the known mechanisms of plasticity that are likely to underlie these map changes, with particular reference to the differences and similarities that exist between

  10. An experimental study of permeability development as a function of crystal-free melt viscosity

    NASA Astrophysics Data System (ADS)

    Lindoo, A.; Larsen, J. F.; Cashman, K. V.; Dunn, A. L.; Neill, O. K.

    2016-02-01

    Permeability development in magmas controls gas escape and, as a consequence, modulates eruptive activity. To date, there are few experimental controls on bubble growth and permeability development, particularly in low viscosity melts. To address this knowledge gap, we have run controlled decompression experiments on crystal-free rhyolite (76 wt.% SiO2), rhyodacite (70 wt.% SiO2), K-phonolite (55 wt.% SiO2) and basaltic andesite (54 wt.% SiO2) melts. This suite of experiments allows us to examine controls on the critical porosity at which vesiculating melts become permeable. As starting materials we used both fine powders and solid slabs of pumice, obsidian and annealed starting materials with viscosities of ˜102 to ˜106 Pas. We saturated the experiments with water at 900° (rhyolite, rhyodacite, and phonolite) and 1025 °C (basaltic andesite) at 150 MPa for 2-72 hrs and decompressed samples isothermally to final pressures of 125 to 10 MPa at rates of 0.25-4.11 MPa/s. Sample porosity was calculated from reflected light images of polished charges and permeability was measured using a bench-top gas permeameter and application of the Forchheimer equation to estimate both viscous (k1) and inertial (k2) permeabilities. Degassing conditions were assessed by measuring dissolved water contents using micro-Fourier-Transform Infrared (μ-FTIR) techniques. All experiment charges are impermeable below a critical porosity (ϕc) that varies among melt compositions. For experiments decompressed at 0.25 MPa/s, we find the percolation threshold for rhyolite is 68.3 ± 2.2 vol.%; for rhyodacite is 77.3 ± 3.8 vol.%; and for K-phonolite is 75.6 ± 1.9 vol.%. Rhyolite decompressed at 3-4 MPa/s has a percolation threshold of 74 ± 1.8 vol.%. These results are similar to previous experiments on silicic melts and to high permeability thresholds inferred for silicic pumice. All basaltic andesite melts decompressed at 0.25 MPa/s, in contrast, have permeabilities below the detection limit

  11. Stylus: A System for Evolutionary Experimentation Based on a Protein/Proteome Model with Non-Arbitrary Functional Constraints

    PubMed Central

    Axe, Douglas D.; Dixon, Brendan W.; Lu, Philip

    2008-01-01

    The study of protein evolution is complicated by the vast size of protein sequence space, the huge number of possible protein folds, and the extraordinary complexity of the causal relationships between protein sequence, structure, and function. Much simpler model constructs may therefore provide an attractive complement to experimental studies in this area. Lattice models, which have long been useful in studies of protein folding, have found increasing use here. However, while these models incorporate actual sequences and structures (albeit non-biological ones), they incorporate no actual functions—relying instead on largely arbitrary structural criteria as a proxy for function. In view of the central importance of function to evolution, and the impossibility of incorporating real functional constraints without real function, it is important that protein-like models be developed around real structure–function relationships. Here we describe such a model and introduce open-source software that implements it. The model is based on the structure–function relationship in written language, where structures are two-dimensional ink paths and functions are the meanings that result when these paths form legible characters. To capture something like the hierarchical complexity of protein structure, we use the traditional characters of Chinese origin. Twenty coplanar vectors, encoded by base triplets, act like amino acids in building the character forms. This vector-world model captures many aspects of real proteins, including life-size sequences, a life-size structural repertoire, a realistic genetic code, secondary, tertiary, and quaternary structure, structural domains and motifs, operon-like genetic structures, and layered functional complexity up to a level resembling bacterial genomes and proteomes. Stylus is a full-featured implementation of the vector world for Unix systems. To demonstrate the utility of Stylus, we generated a sample set of homologous vector

  12. Hydrology Role in Sustaining Ecological Functions in the Everglades; an Experimental Approach.

    NASA Astrophysics Data System (ADS)

    Moustafa, Z. Z.; Gawlik, D.; Sklar, F.; Nachabe, M. H.

    2003-12-01

    replication and provides information more rapidly than observational studies in the natural system. The main goal of the research program in LILA is to define hydrologic regimes that sustain a healthy Everglades ecosystem. Results of this research program will contribute to supporting routine water management operations and establishing quantitative targets for the Comprehensive Everglades Restoration Project (CERP) Performance Measures. This research program will help develop and recommend options for hydrologic operation of the Everglades, particularly during flood events, when the flexibility to move water through the system is critical. Our discussion is focused on the effects of sediment transport and water velocities on marsh topography, habitat diversity, and their role in sustaining certain ecological functions in the Everglades.

  13. A comparative cost analysis of polytrauma and neurosurgery Intensive Care Units at an apex trauma care facility in India

    PubMed Central

    Kumar, Parmeshwar; Jithesh, V.; Gupta, Shakti Kumar

    2016-01-01

    Context: Although Intensive Care Units (ICUs) only account for 10% of the hospital beds, they consume nearly 22% of the hospital resources. Few definitive costing studies have been conducted in Indian settings that would help determine appropriate resource allocation. Aim: The aim of this study was to evaluate and compare the cost of intensive care delivery between multispecialty and neurosurgery ICUs at an apex trauma care facility in India. Materials and Methods: The study was conducted in a polytrauma and neurosurgery ICU at a 203-bedded Level IV trauma care facility in New Delhi, India, from May 1, 2012 to June 30, 2012. The study was cross-sectional, retrospective, and record-based. Traditional costing was used to arrive at the cost for both direct and indirect cost estimates. The cost centers included in the study were building cost, equipment cost, human resources, materials and supplies, clinical and nonclinical support services, engineering maintenance cost, and biomedical waste management. Statistical Analysis: Statistical analysis was performed by Fisher's two tailed t-test. Results: Total cost/bed/day for the multispecialty ICU was Rs. 14,976.9/- and for the neurosurgery ICU, it was Rs. 14,306.7/-, workforce constituting nearly half of the expenditure in both ICUs. The cost center wise and overall difference in the cost among the ICUs were statistically significant. Conclusions: Quantification of expenditure in running an ICU in a trauma center would assist health-care decision makers in better allocation of resources. Although multispecialty ICUs are more cost-effective, other factors will also play a role in defining the kind of ICU that needs to be designed. PMID:27555693

  14. Prenatal Intestinal Obstruction Affects the Myenteric Plexus and Causes Functional Bowel Impairment in Fetal Rat Experimental Model of Intestinal Atresia

    PubMed Central

    Khen-Dunlop, Naziha; Sarnacki, Sabine; Victor, Anais; Grosos, Celine; Menard, Sandrine; Soret, Rodolphe; Goudin, Nicolas; Pousset, Maud; Sauvat, Frederique; Revillon, Yann; Cerf-Bensussan, Nadine; Neunlist, Michel

    2013-01-01

    Background Intestinal atresia is a rare congenital disorder with an incidence of 3/10 000 birth. About one-third of patients have severe intestinal dysfunction after surgical repair. We examined whether prenatal gastrointestinal obstruction might effect on the myenteric plexus and account for subsequent functional disorders. Methodology/Principal Findings We studied a rat model of surgically induced antenatal atresia, comparing intestinal samples from both sides of the obstruction and with healthy rat pups controls. Whole-mount preparations of the myenteric plexus were stained for choline acetyltransferase (ChAT) and nitric oxide synthase (nNOS). Quantitative reverse transcription PCR was used to analyze mRNAs for inflammatory markers. Functional motility and permeability analyses were performed in vitro. Phenotypic studies were also performed in 8 newborns with intestinal atresia. In the experimental model, the proportion of nNOS-immunoreactive neurons was similar in proximal and distal segments (6.7±4.6% vs 5.6±4.2%, p = 0.25), but proximal segments contained a higher proportion of ChAT-immunoreactive neurons (13.2±6.2% vs 7.5±4.3%, p = 0.005). Phenotypic changes were associated with a 100-fold lower concentration-dependent contractile response to carbachol and a 1.6-fold higher EFS-induced contractile response in proximal compared to distal segments. Transcellular (p = 0.002) but not paracellular permeability was increased. Comparison with controls showed that modifications involved not only proximal but also distal segments. Phenotypic studies in human atresia confirmed the changes in ChAT expression. Conclusion Experimental atresia in fetal rat induces differential myenteric plexus phenotypical as well as functional changes (motility and permeability) between the two sides of the obstruction. Delineating these changes might help to identify markers predictive of motility dysfunction and to define guidelines for post-surgical care. PMID:23667464

  15. First Experiences in Intensity Modulated Radiation Surgery at the National Institute of Neurology and Neurosurgery: A Dosimetric Point of View

    NASA Astrophysics Data System (ADS)

    Lárraga-Gutiérrez, José M.; Celis-López, Miguel A.

    2003-09-01

    The National Institute of Neurology and Neurosurgery in Mexico City has acquired a Novalis® shaped beam radiosurgery unit. The institute is pioneer in the use of new technologies for neuroscience. The Novalis® unit allows the use of conformal beam radiosurgery/therapy and the more advanced modality of conformal therapy: Intensity Modulated Radiation Therapy (IMRT). In the present work we present the first cases of treatments that use the IMRT technique and show its ability to protect organs at risk, such as brainstem and optical vias.

  16. Approach-specific multi-grid anatomical modeling for neurosurgery simulation with public-domain and open-source software

    NASA Astrophysics Data System (ADS)

    Audette, Michel A.; Rivière, Denis; Law, Charles; Ibanez, Luis; Aylward, Stephen R.; Finet, Julien; Wu, Xunlei; Ewend, Matthew G.

    2011-03-01

    We present on-going work on multi-resolution sulcal-separable meshing for approach-specific neurosurgery simulation, in conjunction multi-grid and Total Lagrangian Explicit Dynamics finite elements. Conflicting requirements of interactive nonlinear finite elements and small structures lead to a multi-grid framework. Implications for meshing are explicit control over resolution, and prior knowledge of the intended neurosurgical approach and intended path. This information is used to define a subvolume of clinical interest, within some distance of the path and the target pathology. Restricted to this subvolume are a tetrahedralization of finer resolution, the representation of critical tissues, and sulcal separability constraint for all mesh levels.

  17. FUNCTIONAL RECOVERY FOLLOWING MOTOR CORTEX LESIONS IN NON-HUMAN PRIMATES: EXPERIMENTAL IMPLICATIONS FOR HUMAN STROKE PATIENTS

    PubMed Central

    Darling, Warren G.; Pizzimenti, Marc A.; Morecraft, Robert J.

    2013-01-01

    This review discusses selected classical works and contemporary research on recovery of contralesional fine hand motor function following lesions to motor areas of the cerebral cortex in non-human primates. Findings from both the classical literature and contemporary studies show that lesions of cortical motor areas induce paresis initially, but are followed by remarkable recovery of fine hand/digit motor function that depends on lesion size and post-lesion training. Indeed, in recent work where considerable quantification of fine digit function associated with grasping and manipulating small objects has been observed, very favorable recovery is possible with minimal forced use of the contralesional limb. Studies of the mechanisms underlying recovery have shown that following small lesions of the digit areas of primary motor cortex (M1), there is expansion of the digit motor representations into areas of M1 that did not produce digit movements prior to the lesion. However, after larger lesions involving the elbow, wrist and digit areas of M1, no such expansion of the motor representation was observed, suggesting that recovery was due to other cortical or subcortical areas taking over control of hand/digit movements. Recently, we showed that one possible mechanism of recovery after lesion to the arm areas of M1 and lateral premotor cortex is enhancement of corticospinal projections from the medially located supplementary motor area (M2) to spinal cord laminae containing neurons which have lost substantial input from the lateral motor areas and play a critical role in reaching and digit movements. Because human stroke and brain injury patients show variable, and usually poorer, recovery of hand motor function than that of nonhuman primates after motor cortex damage, we conclude with a discussion of implications of this work for further experimentation to improve recovery of hand function in human stroke patients. PMID:21960307

  18. Patient dose estimation from CT scans at the Mexican National Neurology and Neurosurgery Institute

    SciTech Connect

    Alva-Sánchez, Héctor

    2014-11-07

    In the radiology department of the Mexican National Institute of Neurology and Neurosurgery, a dedicated institute in Mexico City, on average 19.3 computed tomography (CT) examinations are performed daily on hospitalized patients for neurological disease diagnosis, control scans and follow-up imaging. The purpose of this work was to estimate the effective dose received by hospitalized patients who underwent a diagnostic CT scan using typical effective dose values for all CT types and to obtain the estimated effective dose distributions received by surgical and non-surgical patients. Effective patient doses were estimated from values per study type reported in the applications guide provided by the scanner manufacturer. This retrospective study included all hospitalized patients who underwent a diagnostic CT scan between 1 January 2011 and 31 December 2012. A total of 8777 CT scans were performed in this two-year period. Simple brain scan was the CT type performed the most (74.3%) followed by contrasted brain scan (6.1%) and head angiotomography (5.7%). The average number of CT scans per patient was 2.83; the average effective dose per patient was 7.9 mSv; the mean estimated radiation dose was significantly higher for surgical (9.1 mSv) than non-surgical patients (6.0 mSv). Three percent of the patients had 10 or more brain CT scans and exceeded the organ radiation dose threshold set by the International Commission on Radiological Protection for deterministic effects of the eye-lens. Although radiation patient doses from CT scans were in general relatively low, 187 patients received a high effective dose (>20 mSv) and 3% might develop cataract from cumulative doses to the eye lens.

  19. Patient dose estimation from CT scans at the Mexican National Neurology and Neurosurgery Institute

    NASA Astrophysics Data System (ADS)

    Alva-Sánchez, Héctor; Reynoso-Mejía, Alberto; Casares-Cruz, Katiuzka; Taboada-Barajas, Jesús

    2014-11-01

    In the radiology department of the Mexican National Institute of Neurology and Neurosurgery, a dedicated institute in Mexico City, on average 19.3 computed tomography (CT) examinations are performed daily on hospitalized patients for neurological disease diagnosis, control scans and follow-up imaging. The purpose of this work was to estimate the effective dose received by hospitalized patients who underwent a diagnostic CT scan using typical effective dose values for all CT types and to obtain the estimated effective dose distributions received by surgical and non-surgical patients. Effective patient doses were estimated from values per study type reported in the applications guide provided by the scanner manufacturer. This retrospective study included all hospitalized patients who underwent a diagnostic CT scan between 1 January 2011 and 31 December 2012. A total of 8777 CT scans were performed in this two-year period. Simple brain scan was the CT type performed the most (74.3%) followed by contrasted brain scan (6.1%) and head angiotomography (5.7%). The average number of CT scans per patient was 2.83; the average effective dose per patient was 7.9 mSv; the mean estimated radiation dose was significantly higher for surgical (9.1 mSv) than non-surgical patients (6.0 mSv). Three percent of the patients had 10 or more brain CT scans and exceeded the organ radiation dose threshold set by the International Commission on Radiological Protection for deterministic effects of the eye-lens. Although radiation patient doses from CT scans were in general relatively low, 187 patients received a high effective dose (>20 mSv) and 3% might develop cataract from cumulative doses to the eye lens.

  20. Does chlorhexidine and povidone-iodine preoperative antisepsis reduce surgical site infection in cranial neurosurgery?

    PubMed

    Davies, B M; Patel, H C

    2016-07-01

    Introduction Surgical site infection (SSI) is a significant cause of postoperative morbidity and mortality. Effective preoperative antisepsis is a recognised prophylactic, with commonly used agents including chlorhexidine (CHG) and povidone-iodine (PVI). However, there is emerging evidence to suggest an additional benefit when they are used in combination. Methods We analysed data from our prospective SSI database on patients undergoing clean cranial neurosurgery between October 2011 and April 2014. We compared the case-mix adjusted odds of developing a SSI in patients undergoing skin preparation with CGH or PVI alone or in combination. Results SSIs were detected in 2.6% of 1146 cases. Antisepsis with PVI alone was performed in 654 (57%) procedures, while 276 (24%) had CHG alone and 216 (19%) CHG and PVI together. SSIs were associated with longer operating time (p<0.001) and younger age (p=0.03). Surgery type (p<0.001) and length of operation (p<0.001) were significantly different between antisepsis groups. In a binary logistic regression model, CHG and PVI was associated with a significant reduction in the likelihood of developing an SSI (adjusted odds ratio [AOR] 0.12, 95% confidence interval [CI] 0.02-0.63) than either agent alone. There was no difference in SSI rates between CHG and PVI alone (AOR 0.60, 95% CI 0.24-1.5). Conclusions Combination skin preparation with CHG and PVI significantly reduced SSI rates compared to CHG or PVI alone. A prospective, randomized study validating these findings is now warranted. PMID:27055411

  1. The effect of skin surface warming on pre-operative anxiety in neurosurgery patients.

    PubMed

    Kimberger, O; Illievich, U; Lenhardt, R

    2007-02-01

    Skin surface warming of patients not only improves thermal comfort, but has been shown to reduce anxiety in a pre-hospital setting. We tested the hypothesis that pre-operative warming can reduce pre-operative anxiety as effectively as a conventional dose of intravenous midazolam in patients undergoing neurosurgery. We randomly allocated 80 patients to four groups in the pre-operative holding area. Treatment was applied for 30-45 min with (1) passive insulation and placebo; (2) passive insulation and intravenous midazolam (30 microg.kg-1); (3) warming with forced-air and placebo; and (4) warming with forced-air and intravenous midazolam (30 microg.kg-1). Thermal comfort levels (VAS 0-100 mm) and anxiety levels (VAS 0-100 mm, Spielberger State-Trait Anxiety Inventory) were assessed twice: before the designated treatment was started and before induction of anaesthesia. In the midazolam and the midazolam/warming groups, anxiety VAS and Spielberger state anxiety scores decreased by -19 (95% CI: -29 to -9, p<0.01) and -10 (95% CI: -14 to -6, p<0.01), respectively. In the warming and the combined groups, thermal VAS increased by +26 (95% CI: 17-34, p<0.01). Pre-operative warming did not reduce anxiety VAS (p=0.11) or Spielberger state anxiety (p=0.19). The results of our study indicate that pre-operative warming can be recommended solely to improve thermal comfort, not to replace anxiolytic premedication regimens. PMID:17223806

  2. Retractor-induced brain shift compensation in image-guided neurosurgery

    NASA Astrophysics Data System (ADS)

    Fan, Xiaoyao; Ji, Songbai; Hartov, Alex; Roberts, David; Paulsen, Keith

    2013-03-01

    In image-guided neurosurgery, intraoperative brain shift significantly degrades the accuracy of neuronavigation that is solely based on preoperative magnetic resonance images (pMR). To compensate for brain deformation and to maintain the accuracy in image guidance achieved at the start of surgery, biomechanical models have been developed to simulate brain deformation and to produce model-updated MR images (uMR) to compensate for brain shift. To-date, most studies have focused on shift compensation at early stages of surgery (i.e., updated images are only produced after craniotomy and durotomy). Simulating surgical events at later stages such as retraction and tissue resection are, perhaps, clinically more relevant because of the typically much larger magnitudes of brain deformation. However, these surgical events are substantially more complex in nature, thereby posing significant challenges in model-based brain shift compensation strategies. In this study, we present results from an initial investigation to simulate retractor-induced brain deformation through a biomechanical finite element (FE) model where whole-brain deformation assimilated from intraoperative data was used produce uMR for improved accuracy in image guidance. Specifically, intensity-encoded 3D surface profiles at the exposed cortical area were reconstructed from intraoperative stereovision (iSV) images before and after tissue retraction. Retractor-induced surface displacements were then derived by coregistering the surfaces and served as sparse displacement data to drive the FE model. With one patient case, we show that our technique is able to produce uMR that agrees well with the reconstructed iSV surface after retraction. The computational cost to simulate retractor-induced brain deformation was approximately 10 min. In addition, our approach introduces minimal interruption to the surgical workflow, suggesting the potential for its clinical application.

  3. Graphical user interfaces for simulation of brain deformation in image-guided neurosurgery

    NASA Astrophysics Data System (ADS)

    Fan, Xiaoyao; Ji, Songbai; Valdes, Pablo; Roberts, David W.; Hartov, Alex; Paulsen, Keith D.

    2010-02-01

    In image-guided neurosurgery, preoperative images are typically used for surgical planning and intraoperative guidance. The accuracy of preoperative images can be significantly compromised by intraoperative brain deformation. To compensate for brain shift, biomechanical finite element models have been used to assimilate intraoperative data to simulate brain deformation. The clinical feasibility of the approach strongly depends on its accuracy and efficiency. In order to facilitate and streamline data flow, we have developed graphical user interfaces (GUIs) to provide efficient image updates in the operating room (OR). The GUIs are organized in a top-down hierarchy with a main control panel that invokes and monitors a series of sub-GUIs dedicated to perform tasks involved in various aspects of computations of whole-brain deformation. These GUIs are used to segment brain, generate case-specific brain meshes, and assign and visualize case-specific boundary conditions (BC). Registration between intraoperative ultrasound (iUS) images acquired pre- and post-durotomy is also facilitated by a dedicated GUI to extract sparse displacement data used to drive a biomechanical model. Computed whole-brain deformation is then used to morph preoperative MR images (pMR) to generate a model-updated image set (i.e., uMR) for intraoperative guidance (accuracy of 1-2 mm). These task-driven GUIs have been designed to be fault-tolerant, user-friendly, and with sufficient automation. In this paper, we present the modular components of the GUIs and demonstrate the typical workflow through a clinical patient case.

  4. Intracranial meningiomas managed at Memfys hospital for neurosurgery in Enugu, Nigeria

    PubMed Central

    Mezue, Wilfred C; Ohaegbulam, Samuel C; Ndubuisi, Chika C; Chikani, Mark C; Achebe, David S

    2012-01-01

    Introduction: The epidemiology and pathology of meningioma in Nigeria are still evolving and little has been published about this tumor in Nigeria, especially in the southeast region. The aim of this paper is to compare the characteristics of intracranial meningioma managed in our center with the pattern reported in the literature worldwide. Materials and Methods: Retrospective analysis of prospectively recorded data of patients managed for intracranial meningioma between January 2002 and December 2010 at a Private neurosurgery Hospital in Enugu, Nigeria. We excluded patients whose histology results were inconclusive. Results: Meningiomas constituted 23.8% of all intracranial tumors seen in the period. The male to female ratio was 1:1.1. The peak age range for males and females were in the fifth and sixth decades, respectively. The most common location is the Olfactory groove in 26.5% of patients followed by convexity in 23.5%. Presentation varied with anatomical location of tumor. Patients with olfactory groove meningioma (OGM) mostly presented late with personality changes and evidence of raised ICP. Tuberculum sellar and sphenoid region tumors presented earlier with visual impairment with or without hormonal abnormalities. Seizures occurred in 30.9% of all patients and in 45% of those with convexity meningiomas. Only 57.4% of the patients were managed surgically and there was no gender difference in this group. WHO grade1 tumors were the most common histological types occurring in 84.6%. One patient had atypical meningioma and two had anaplastic tumors. Conclusion: The pattern of meningioma in our area may have geographical differences in location and histology. Childhood meningioma was rare. PMID:23188985

  5. Towards the development of a spring-based continuum robot for neurosurgery

    NASA Astrophysics Data System (ADS)

    Kim, Yeongjin; Cheng, Shing Shin; Desai, Jaydev P.

    2015-03-01

    Brain tumor is usually life threatening due to the uncontrolled growth of abnormal cells native to the brain or the spread of tumor cells from outside the central nervous system to the brain. The risks involved in carrying out surgery within such a complex organ can cause severe anxiety in cancer patients. However, neurosurgery, which remains one of the more effective ways of treating brain tumors focused in a confined volume, can have a tremendously increased success rate if the appropriate imaging modality is used for complete tumor removal. Magnetic resonance imaging (MRI) provides excellent soft-tissue contrast and is the imaging modality of choice for brain tumor imaging. MRI combined with continuum soft robotics has immense potential to be the revolutionary treatment technique in the field of brain cancer. It eliminates the concern of hand tremor and guarantees a more precise procedure. One of the prototypes of Minimally Invasive Neurosurgical Intracranial Robot (MINIR-II), which can be classified as a continuum soft robot, consists of a snake-like body made of three segments of rapid prototyped plastic springs. It provides improved dexterity with higher degrees of freedom and independent joint control. It is MRI-compatible, allowing surgeons to track and determine the real-time location of the robot relative to the brain tumor target. The robot was manufactured in a single piece using rapid prototyping technology at a low cost, allowing it to disposable after each use. MINIR-II has two DOFs at each segment with both joints controlled by two pairs of MRI-compatible SMA spring actuators. Preliminary motion tests have been carried out using vision-tracking method and the robot was able to move to different positions based on user commands.

  6. The impact of a patient education bundle on neurosurgery patient satisfaction

    PubMed Central

    Kliot, Tamara; Zygourakis, Corinna C.; Imershein, Sarah; Lau, Catherine; Kliot, Michel

    2015-01-01

    Background: As reimbursements and hospital/physician performance become ever more reliant on Hospital Consumer Assessment of Health Care Providers and Systems (HCAHPS) and other quality metrics, physicians are increasingly incentivized to improve patient satisfaction. Methods: A faculty and resident team at the University of California, San Francisco (UCSF) Department of Neurological Surgery developed and implemented a Patient Education Bundle. This consisted of two parts: The first was preoperative expectation letters (designed to inform patients of what to expect before, during, and after their hospitalization for a neurosurgical procedure); the second was a trifold brochure with names, photographs, and specialty/training information about the attending surgeons, resident physicians, and nurse practitioners on the neurosurgical service. We assessed patient satisfaction, as measured by HCAHPS scores and a brief survey tailored to our specific intervention, both before and after our Patient Education Bundle intervention. Results: Prior to our intervention, 74.6% of patients responded that the MD always explained information in a way that was easy to understand. After our intervention, 78.7% of patients responded that the MD always explained information in a way that was easy to understand. “Neurosurgery Patient Satisfaction survey” results showed that 83% remembered receiving the preoperative letter; of those received the letter, 93% found the letter helpful; and 100% thought that the letter should be continued. Conclusion: Although effects were modest, we believe that patient education strategies, as modeled in our bundle, can improve patients’ hospital experiences and have a positive impact on physician performance scores and hospital ratings. PMID:26664909

  7. Genetic Linkage of Soil Carbon Pools and Microbial Functions in Subtropical Freshwater Wetlands in Response to Experimental Warming

    PubMed Central

    Wang, Hang; He, Zhili; Lu, Zhenmei; Zhou, Jizhong; Van Nostrand, Joy D.; Xu, Xinhua

    2012-01-01

    Rising climate temperatures in the future are predicted to accelerate the microbial decomposition of soil organic matter. A field microcosm experiment was carried out to examine the impact of soil warming in freshwater wetlands on different organic carbon (C) pools and associated microbial functional responses. GeoChip 4.0, a functional gene microarray, was used to determine microbial gene diversity and functional potential for C degradation. Experimental warming significantly increased soil pore water dissolved organic C and phosphorus (P) concentrations, leading to a higher potential for C emission and P export. Such losses of total organic C stored in soil could be traced back to the decomposition of recalcitrant organic C. Warming preferentially stimulated genes for degrading recalcitrant C over labile C. This was especially true for genes encoding cellobiase and mnp for cellulose and lignin degradation, respectively. We confirmed this with warming-enhanced polyphenol oxidase and peroxidase activities for recalcitrant C acquisition and greater increases in recalcitrant C use efficiency than in labile C use efficiency (average percentage increases of 48% versus 28%, respectively). The relative abundance of lignin-degrading genes increased by 15% under warming; meanwhile, soil fungi, as the primary decomposers of lignin, were greater in abundance by 27%. This work suggests that future warming may enhance the potential for accelerated fungal decomposition of lignin-like compounds, leading to greater microbially mediated C losses than previously estimated in freshwater wetlands. PMID:22923398

  8. Experimental and theoretical studies on compositions, structures, and IR and NMR spectra of functionalized protic ionic liquids.

    PubMed

    Cui, Yingna; Yin, Jingmei; Li, Changping; Li, Shenmin; Wang, Ailing; Yang, Guang; Jia, Yingping

    2016-07-20

    The compositions and structures of amine-based functionalized protic ionic liquids (PILs), namely N,N-dimethyl(cyanoethyl)ammonium propionate (DMCEAP) and N,N-dimethyl(hydroxyethyl)ammonium propionate (DMEOAP) have been investigated systematically by IR and (1)H NMR spectroscopy and density functional theory (DFT) calculations. Analysis of the IR spectra suggests that both DMCEAP and DMEOAP are composed of neutral and ionized species in the liquid phase, the former one mainly existing in the state of precursor molecules, and the latter mainly as ion-pairs. The ratio of precursor molecules to ion-pairs in the liquid phase depends on the types of precursors, especially the functional groups of cations. (1)H NMR spectra indicate that there is a dynamic equilibrium between the neutral and ionized species, probably due to the formation of some intermediates in the PILs. The DFT calculations have been carried out to reveal the conformation, and obtain the corresponding IR and (1)H NMR spectra of the neutral and ionized species, so that the theoretical support to the experimental results can be provided. The present study will help understand the properties of PILs and provide guidance for further applications of PILs. PMID:27385035

  9. Theoretical and Experimental Investigation of Random Gust Loads Part I : Aerodynamic Transfer Function of a Simple Wing Configuration in Incompressible Flow

    NASA Technical Reports Server (NTRS)

    Hakkinen, Raimo J; Richardson, A S , Jr

    1957-01-01

    Sinusoidally oscillating downwash and lift produced on a simple rigid airfoil were measured and compared with calculated values. Statistically stationary random downwash and the corresponding lift on a simple rigid airfoil were also measured and the transfer functions between their power spectra determined. The random experimental values are compared with theoretically approximated values. Limitations of the experimental technique and the need for more extensive experimental data are discussed.

  10. Exocrine and endocrine testicular function during the treatment of experimental orchitis and nonspecific orchoepididymitis by low-energy laser radiation

    NASA Astrophysics Data System (ADS)

    Reznikov, Leonid L.; Pupkova, Ludmila S.; Bell, H.; Murzin, Alexander G.

    1995-05-01

    Investigations into the biological effects of low-energy laser radiation (LLR) are characterized by a score of challenges, which are due primarily to a cascade of laser-induced and sometimes antagonistic processes. To investigate these processes on various biologic levels, we analyzed local and general effects of LLR on the exocrine and endocrine functions of the accessory sex glands in experimentally induced orchitis and orchoepididymitis in rabbits, and in clinical studies on male patients. The results indicate that LLR may alter the inflammatory response, including the exudative reaction, macrophage migration, and fibroblast activity. Furthermore, LLR may result in changes in serum concentrations of LH, FSH, and ACTH, prolactin, testosterone, cortisol and aldosterone. Some of these changes may be at least partially responsible for the well-known anti-inflammatory effects of LLR.

  11. Compressibility and hardness of Co-based bulk metallic glass: A combined experimental and density functional theory study

    SciTech Connect

    Wang Jianfeng; Li Ran; Xu Tao; Li Yan; Liu Zengqian; Huang Lu; Hua Nengbin; Zhang Tao; Xiao Ruijuan; Li Gong; Li Yanchun

    2011-10-10

    An incompressible Co{sub 54}Ta{sub 11}B{sub 35} bulk metallic glass (BMG) was investigated using in situ high-pressure synchrotron diffraction and nanoindendation. The elastic constants were deduced from the experiments based on the isotropic model. The Vickers hardness was measured to be 17.1 GPa. The elastic moduli and hardness are the highest values known in BMGs. The theoretically calculated elastic properties by density-functional study were well consistent with experimental measurements. The analysis of charge density and bonding character indicates the covalent character of Co-B and B-B bonds, underlying the unusually high elastic modulus and hardness in this material.

  12. Use of Modern Chemical Protein Synthesis and Advanced Fluorescent Assay Techniques to Experimentally Validate the Functional Annotation of Microbial Genomes

    SciTech Connect

    Kent, Stephen

    2012-07-20

    The objective of this research program was to prototype methods for the chemical synthesis of predicted protein molecules in annotated microbial genomes. High throughput chemical methods were to be used to make large numbers of predicted proteins and protein domains, based on microbial genome sequences. Microscale chemical synthesis methods for the parallel preparation of peptide-thioester building blocks were developed; these peptide segments are used for the parallel chemical synthesis of proteins and protein domains. Ultimately, it is envisaged that these synthetic molecules would be ‘printed’ in spatially addressable arrays. The unique ability of total synthesis to precision label protein molecules with dyes and with chemical or biochemical ‘tags’ can be used to facilitate novel assay technologies adapted from state-of-the art single molecule fluorescence detection techniques. In the future, in conjunction with modern laboratory automation this integrated set of techniques will enable high throughput experimental validation of the functional annotation of microbial genomes.

  13. Nutritional influences of overfeeding on experimental outcomes in laboratory mice: consequences for gut microbiota and other functional studies.

    PubMed

    Bischoff, Stephan C; Volynets, Valentina

    2016-08-01

    Data from literature suggests that laboratory mice are often overfed and malnourished. This might have several reasons, including: (i) we usually offer an ad libitum diet, which is not the natural way of feeding for a wild mouse; (ii) many commercial diets we use contain rather high amounts of carbohydrates, particularly of sugars, and low amounts of fat; and (iii) laboratory mice live in a warm and constricted environment in which energy expenditure is lower than in the wild. Such selective or global overfeeding in laboratory mice, which resembles the widespread overfeeding in humans, although it does not always result in overweight, likely affects a number of outcome variables analyzed in laboratory mice, such as microbiota composition and function, metabolic alterations, longevity, intestinal permeability and inflammation. Therefore, a careful selection of experimental diets and their way of administration, as well as detailed documentation, is mandatory in order to understand and compare scientific data obtained from different mouse experiments. PMID:27432516

  14. Functional characterization of α1-adrenoceptor subtypes in vascular tissues using different experimental approaches:a comparative study

    PubMed Central

    Gisbert, Regina; Madrero, Yolanda; Sabino, Valentina; Noguera, M Antonia; Ivorra, M Dolores; D'Ocon, Pilar

    2003-01-01

    The α1-adrenergic responses of rat aorta and tail artery have been analysed measuring the contractility and the inositol phosphate (IP) formation induced by noradrenaline. Three antagonists, prazosin, 5-methylurapidil (α1A selective) and BMY 7378 (α1D selective) have been used in different experimental procedures. Noradrenaline possesses a greater potency inducing contraction and IP accumulation in aorta (pEC50-contraction=7.32±0.04; pEC50-IPs=6.03±0.08) than in the tail artery (pEC50-contraction=5.71±0.07; pEC50-IPs=5.51±0.10). Although the maximum contraction was similar in both tissues (Emax-tail=619.1±55.6 mg; Emax-aorta-698.2±40.8 mg), there were marked differences in the ability of these tissues to generate intracellular second messengers the tail artery being more efficient (Emax-tail=1060±147%; Emax-aorta=108.1±16.9%). Concentration response curves of noradrenaline in presence of antagonist together with concentration inhibition curves for antagonists added before (CICb) or after (CICa) noradrenaline-induced maximal response in Ca2+-containing or Ca2+-free medium have been performed. A comparative analysis of the different procedures as well as the mathematical approaches used in each case to calculate the antagonist potencies, were completed. The CICa was the simplest method to characterize the predominant α1-adrenoceptor subtype involved in the functional response of a tissue. In aorta, where constitutively active α1D-adrenoeptors are present, the use of different experimental procedures evidenced a complex equilibrium between α1D- and α1A-adrenoceptor subtypes. The appropriate management of LiCl in IP accumulation studies allowed us to reproduce the different experimental procedures performed in contractile experiments giving more technical possibilities to this methodology. PMID:12540527

  15. Understanding the Role of Ti in Reversible Hydrogen Storage as Sodium Alanate: A Combined Experimental and Density Functional Theoretical Approach

    SciTech Connect

    Chaudhuri,S.; Graetz, J.; Ignatov, A.; Reilly, J.; Muckerman, J.

    2006-01-01

    We report the results of an experimental and theoretical study of hydrogen storage in sodium alanate (NaAlH{sub 4}). Reversible hydrogen storage in this material is dependent on the presence of 2-4% Ti dopant. Our combined study shows that the role of Ti may be linked entirely to Ti-containing active catalytic sites in the metallic Al phase present in the dehydrogenated NaAlH{sub 4}. The EXAFS data presented here show that dehydrogenated samples contain a highly disordered distribution of Ti-Al distances with no long-range order beyond the second coordination sphere. We have used density functional theory techniques to calculate the chemical potential of possible Ti arrangements on an Al(001) surface for Ti coverages ranging from 0.125 to 0.5 monolayer (ML) and have identified those that can chemisorb molecular hydrogen via spontaneous or only moderately activated pathways. The chemisorption process exhibits a characteristic nodal symmetry property for the low-barrier sites: the incipient doped surface-H2 adduct's highest occupied molecular orbital (HOMO) incorporates the {sigma}* antibonding molecular orbital of hydrogen, allowing the transfer of charge density from the surface to dissociate the molecular hydrogen. This work also proposes a plausible mechanism for the transport of an aluminum hydride species back into the NaH lattice that is supported by Car-Parrinello molecular dynamics (CPMD) simulations of the stability and mobility of aluminum clusters (alanes) on Al(001). As an experimental validation of the proposed role of titanium and the subsequent diffusion of alanes, we demonstrate experimentally that AlH{sub 3} reacts with NaH to form NaAlH{sub 4} without any requirement of a catalyst or hydrogen overpressure.

  16. Understanding the role of Ti in reversible hydrogen storage as sodium alanate: a combined experimental and density functional theoretical approach.

    PubMed

    Chaudhuri, Santanu; Graetz, Jason; Ignatov, Alex; Reilly, James J; Muckerman, James T

    2006-09-01

    We report the results of an experimental and theoretical study of hydrogen storage in sodium alanate (NaAlH(4)). Reversible hydrogen storage in this material is dependent on the presence of 2-4% Ti dopant. Our combined study shows that the role of Ti may be linked entirely to Ti-containing active catalytic sites in the metallic Al phase present in the dehydrogenated NaAlH(4). The EXAFS data presented here show that dehydrogenated samples contain a highly disordered distribution of Ti-Al distances with no long-range order beyond the second coordination sphere. We have used density functional theory techniques to calculate the chemical potential of possible Ti arrangements on an Al(001) surface for Ti coverages ranging from 0.125 to 0.5 monolayer (ML) and have identified those that can chemisorb molecular hydrogen via spontaneous or only moderately activated pathways. The chemisorption process exhibits a characteristic nodal symmetry property for the low-barrier sites: the incipient doped surface-H(2) adduct's highest occupied molecular orbital (HOMO) incorporates the sigma antibonding molecular orbital of hydrogen, allowing the transfer of charge density from the surface to dissociate the molecular hydrogen. This work also proposes a plausible mechanism for the transport of an aluminum hydride species back into the NaH lattice that is supported by Car-Parrinello molecular dynamics (CPMD) simulations of the stability and mobility of aluminum clusters (alanes) on Al(001). As an experimental validation of the proposed role of titanium and the subsequent diffusion of alanes, we demonstrate experimentally that AlH(3) reacts with NaH to form NaAlH(4) without any requirement of a catalyst or hydrogen overpressure. PMID:16939263

  17. Detection and effects on platelet function of anti-platelet antibody in mule foals with experimentally induced neonatal alloimmune thrombocytopenia.

    PubMed

    Ramirez, S; Gaunt, S D; McClure, J J; Oliver, J

    1999-01-01

    Horse mares carrying mule foals were immunized during the last trimester of pregnancy with whole acid-citrate-dextrose-anticoagulated donkey blood to experimentally induce neonatal alloimmune thrombocytopenia. Thrombocytopenia occurred in the neonatal mule foals born to immunized horse mares within 24 hours after ingestion of their dams' colostrum. Mule foals born to mares not immunized with donkey blood did not develop thrombocytopenia. These findings suggest that antibodies may have been directed against a donkey platelet antigen present in the mule foals but not present in their dams. The objectives of this study were to determine whether anti-platelet antibody could be detected in mule foals with experimentally induced neonatal alloimmune thrombocytopenia, to identify any platelet proteins recognized by serum antibody in these foals, and to determine if platelet function was altered by sera from these mule foals. An indirect enzyme-linked immunosorbent assay demonstrated significantly higher absorption at 1:200 of platelet-bindable immunoglobulin G in serum from thrombocytopenic mule foals, compared with nonthrombocytopenic mule foals. Sera from thrombocytopenic and nonthrombocytopenic mule foals produced similar binding patterns in western immunoblots with donkey platelet proteins separated on sodium dodecyl sulfate polyacrylamide gels. Maximal platelet aggregation and relative slope of aggregation in response to collagen were significantly inhibited after incubation with sera from thrombocytopenic mule foals. These results suggest that mule foals with induced alloimmune thrombocytopenia have serum antibodies that bind to platelets and may compete with collagen binding sites to impair platelet aggregation. PMID:10587252

  18. Structural and optical properties of Cu doped SnO2 nanoparticles: An experimental and density functional study

    NASA Astrophysics Data System (ADS)

    Chetri, Pawan; Saikia, Bhamyarswa; Choudhury, Amarjyoti

    2013-06-01

    The paper investigates, both theoretically and experimentally, the structural and optical changes in SnO2 system brought about by introduction of Cu in a SnO2 system. On the experimental front, a cost effective sol-gel technique is used to prepare hexagonal shaped Cu doped SnO2 nanoparticles. The prepared pristine SnO2 nanoparticle is found to be of random shape by transmission electron microscope (TEM) studies. A structural and morphological study is carried out using X-ray diffraction and TEM techniques. The different phonon interaction in the system is observed by Raman spectroscopy while electron paramagnetic resonance and UV-Visible spectroscopy confirms the presence of Cu in 2+ state. First principle calculations have been performed using "density functional theory"-based MedeA Vienna Ab Initio Simulation package on a SnO2 system where Cu is introduced. The introduction of Cu in the SnO2 system brings distortion which is corroborated by the variation in the corresponding bond lengths. The Density of State calculation of Sn16O32 and CuSn15O32 is also performed. Finally, a correlation is established between the experiment and the theory.

  19. Morpho-functional patterns of kidney injury in the experimental leptospirosis of the guinea-pig (L. icterohaemorrhagiae).

    PubMed

    Dávila de Arriaga, A J; Rocha, A S; Yasuda, P H; De Brito, T

    1982-10-01

    Thirty-seven guinea-pigs experimentally infected with a virulent strain of L. icterohaemorrhagiae, were submitted to a renal function study as evaluated through the maximal urinary concentration (MUC) test, blood urea nitrogen (BUN) and afterwards had their kidneys examined by light and electron microscopy. Vascular changes were also studied after the administration of colloidal carbon as a marker. Through the MUC test and BUN determination, two groups of tubulo-interstitial lesions can be visualised, one in animals without renal sufficiency, manifested chiefly by cell edema with RE dilation and another, in animals with renal insufficiency, characterised not only by marked cell edema and mitochondrial changes, but also by proximal tubule regenerative aspects without overt tubular necrosis. Interstitial edema and focal nephritis was prominent in both groups, a finding which minimises their role in the pathogenesis of renal failure in experimental leptospirosis. Vascular injury, affecting the vessels of the renal microcirculation chiefly at the cortico-medular junction, was observed in both groups. Its severity and extension ran parallel to the intensity of the tubular injury. This suggests a simultaneous action of a noxious agent liberated by the leptospires over both structures, tubular damage being accentuated by the local circulatory changes. PMID:7131130

  20. Disentangling direct and indirect effects of experimental grassland management and plant functional-group manipulation on plant and leafhopper diversity

    PubMed Central

    2014-01-01

    Background Plant biodiversity can affect trophic interactions in many ways, including direct bottom-up effects on insects, but is negatively affected by agricultural intensification. Grassland intensification promotes plant productivity, resulting in changes in plant community composition, and impacts on higher trophic levels. Here, we use a novel grassland management experiment combining manipulations of cutting and fertilization with experimental changes in plant functional group composition (independent of management effects) to disentangle the direct and indirect effects of agricultural management on insect herbivore diversity and abundance. We used leafhoppers as model organisms as they are a key insect taxon in grasslands and react rapidly to management changes. Leafhoppers were sampled between May and September 2010 using standardized sweep netting and pan traps. Results Plant diversity, functional group composition and management regime in grasslands affected leafhopper species richness and abundance. Higher cutting frequencies directly led to decreasing leafhopper species richness, presumably due to the higher disturbance frequency and the reduction in food-resource heterogeneity. In contrast, fertilizer application had only a small indirect negative effect via enhanced aboveground plant biomass, reduced plant diversity and changes in functional group composition. The manipulated increase in grass cover had contrasting direct and indirect effects on leafhopper species richness: grass cover directly increased leafhopper species richness, but negatively affected plant diversity, which in turn was positively related to leafhopper species richness. In conclusion, insect diversity is driven in complex direct and indirect ways by grassland management, including changes in functional group composition. Conclusions The availability of preferred food sources and the frequency of disturbance are important direct and indirect drivers of leafhopper species richness

  1. Experimental study of strontium adsorption on anatase nanoparticles as a function of size with a density functional theory and CD model interpretation.

    PubMed

    Ridley, Moira K; Machesky, Michael L; Kubicki, James D

    2015-01-20

    The effect of particle size on the adsorption of Sr(2+) onto monodisperse nanometer diameter (4, 20, and 40 nm) anatase samples has been evaluated quantitatively with macroscopic experimental studies. The adsorption of Sr(2+) onto the anatase particles was evaluated by potentiometric titrations in NaCl media, at two ionic strengths (0.03 and 0.3 m), and over a wide range of pH (3-11) and surface loadings, at a temperature of 25 °C. Adsorption of Sr(2+) to the surface of the 20 and 40 nm diameter samples was similar, whereas the Sr(2+) adsorption titration curves were shallower for the 4 nm diameter samples. At high pH, the smallest particles adsorbed slightly less Sr(2+) than was adsorbed by the larger particles. At the molecular scale, density functional theory (DFT) calculations were used to evaluate the most stable Sr(2+) surface species on the (101) anatase surface (the predominant crystal face). An inner-sphere Sr-tridentate surface species was found to be the most stable. The experimental data were described with a charge distribution (CD) and multisite complexation (MUSIC) model, with a Basic Stern layer description of the electric double layer. The resulting surface complexation model explicitly incorporated the molecular-scale information from the DFT simulation results. For 20 and 40 nm diameter anatase, the CD value for the Sr-tridentate species was calculated using a bond valence interpretation of the DFT-optimized geometry. The CD value for the 4 nm sample was smaller than that for the 20 and 40 nm samples, reflecting the shallower Sr(2+) adsorption titration curves. The adsorption differences between the smallest and larger anatase particles can be rationalized by water being more highly structured near the 4 nm anatase sample and/or the Sr-tridentate surface species may require more well-developed surface terraces than are present on the 4 nm particles. PMID:25517626

  2. Density functional theory study of the shallow boron impurity in 3 C -SiC and comparison with experimental data

    NASA Astrophysics Data System (ADS)

    Petrenko, T. T.; Petrenko, T. L.

    2016-04-01

    In this paper, we present a detailed study of the boron impurity in 3 C -SiC (BS i) in the cluster (CL) and supercell (SC) approximations, using representative local, gradient-corrected, and hybrid density functionals. Comparison of the theoretical spin-Hamiltonian parameters, calculated in the CL approximation using nonlocal density functionals, with the corresponding experimental values for the so-called shallow boron in SiC has proved that the latter is the BSi 0 defect. We analyze the motional effects in the electron paramagnetic resonance spectra, as well as the site dependence of the symmetry and SH parameters of BSi 0. The dependencies of the calculated structural and energetic parameters on the size of the model space both for SC and CL methods are presented. The calculated relative formation energies and transition energy levels for the neutral BS i and BC centers reveal substantial finite-size effects. A simple extrapolation scheme indicates that the supercells with up to 105 atoms are required to achieve the desired accuracy level of 0.1 eV. Calculations suggest that BC impurity is a hyperdeep acceptor, which acts as the electron trap rather than increases the p -type conductivity.

  3. Estimation of the neuromotor system functional state after sciatic nerve neurorrhaphy in experimental conditions of intravenous laser irradiation of blood

    NASA Astrophysics Data System (ADS)

    Nechipurenko, N. I.; Tanin, Leonid V.; Antonov, Ignatii P.; Vasilevskaya, Lyudmila A.; Vlasyuk, P. A.

    1996-12-01

    The speckle-optical methods and the methods of electroneuromyography were used to study the myotonus, the contractional activity of leg muscles and the neuromotor system functional state in intact rabbits and 3 months after the sciatic nerve (SN) neurorrhaphy in conditions of intravenous laser irradiation of blood (ILIB). The blood of animals was exposed to laser radiation with the help of a quartz-polymeric light guide, which has been inserted into the earvein the next day after SN stitching. The radiation power at the light guide output was 2-2.5 mW. Two courses of treatment with a two-week interval have been conducted. It has been established from the speckle-optical study data that ILIB increases the contractional activity of skeletal muscles in animals. The ILIB-therapy after the SN neurorrhaphy normalizes the latent period of M-response and neural cation potential. A tendancy has been revealed to an increase in impulse conduction velocity in motor nerve fibers and in maximal amplitude of the neural action potential. Thus, the ILIB-therapy after SN trauma improves the neuromotor system functional state in experimental animals in the early reinnervation period.

  4. Complementation of Yeast Genes with Human Genes as an Experimental Platform for Functional Testing of Human Genetic Variants

    PubMed Central

    Hamza, Akil; Tammpere, Erik; Kofoed, Megan; Keong, Christelle; Chiang, Jennifer; Giaever, Guri; Nislow, Corey; Hieter, Philip

    2015-01-01

    While the pace of discovery of human genetic variants in tumors, patients, and diverse populations has rapidly accelerated, deciphering their functional consequence has become rate-limiting. Using cross-species complementation, model organisms like the budding yeast, Saccharomyces cerevisiae, can be utilized to fill this gap and serve as a platform for testing human genetic variants. To this end, we performed two parallel screens, a one-to-one complementation screen for essential yeast genes implicated in chromosome instability and a pool-to-pool screen that queried all possible essential yeast genes for rescue of lethality by all possible human homologs. Our work identified 65 human cDNAs that can replace the null allele of essential yeast genes, including the nonorthologous pair yRFT1/hSEC61A1. We chose four human cDNAs (hLIG1, hSSRP1, hPPP1CA, and hPPP1CC) for which their yeast gene counterparts function in chromosome stability and assayed in yeast 35 tumor-specific missense mutations for growth defects and sensitivity to DNA-damaging agents. This resulted in a set of human–yeast gene complementation pairs that allow human genetic variants to be readily characterized in yeast, and a prioritized list of somatic mutations that could contribute to chromosome instability in human tumors. These data establish the utility of this cross-species experimental approach. PMID:26354769

  5. Experimental Determination of the Dynamic Hydraulic Transfer Function for the J-2X Oxidizer Turbopump. Part One; Methodology

    NASA Technical Reports Server (NTRS)

    Zoladz, Tom; Patel, Sandeep; Lee, Erik; Karon, Dave

    2011-01-01

    An advanced methodology for extracting the hydraulic dynamic pump transfer matrix (Yp) for a cavitating liquid rocket engine turbopump inducer+impeller has been developed. The transfer function is required for integrated vehicle pogo stability analysis as well as optimization of local inducer pumping stability. Laboratory pulsed subscale waterflow test of the J-2X oxygen turbo pump is introduced and our new extraction method applied to the data collected. From accurate measures of pump inlet and discharge perturbational mass flows and pressures, and one-dimensional flow models that represents complete waterflow loop physics, we are able to derive Yp and hence extract the characteristic pump parameters: compliance, pump gain, impedance, mass flow gain. Detailed modeling is necessary to accurately translate instrument plane measurements to the pump inlet and discharge and extract Yp. We present the MSFC Dynamic Lump Parameter Fluid Model Framework and describe critical dynamic component details. We report on fit minimization techniques, cost (fitness) function derivation, and resulting model fits to our experimental data are presented. Comparisons are made to alternate techniques for spatially translating measurement stations to actual pump inlet and discharge.

  6. The experimental dielectric function of porous anodic alumina in the infrared region; a comparison with the Maxwell-Garnett model

    NASA Astrophysics Data System (ADS)

    Wäckelgård, Ewa

    1996-06-01

    The infrared reflectance from thin alumina films on metal substrates has a deep minimum for p-polarized light at oblique incidence. This originates from absorption when light couples with a longitudinal optical (LO) phonon mode with k-vector zero. The absorption band is wide for amorphous alumina and is shifted to longer wavelengths for porous oxides compared to non-porous ones. Anodic alumina, prepared in phosphoric acid, with a pore volume fraction of 0.3, has been investigated. The s- and p-polarized reflectance has been measured for selected angles of incidence between 0953-8984/8/23/019/img1 and 0953-8984/8/23/019/img2, and the dielectric function has been determined from these measurements. The effective dielectric function has been calculated using Maxwell-Garnett effective-medium theory for a two-component anisotropic medium consisting of air-filled cylindrical pores perpendicular to the surface in an alumina matrix with optical constants of non-porous evaporated alumina. The theoretical and experimental results are in good agreement, which shows that the redshift of the LO mode absorption for p-polarized light can be explained by the presence of pores.

  7. Passive hind-limb cycling improves cardiac function and reduces cardiovascular disease risk in experimental spinal cord injury

    PubMed Central

    West, Christopher R; Crawford, Mark A; Poormasjedi-Meibod, Malihe-Sadat; Currie, Katharine D; Fallavollita, Andre; Yuen, Violet; McNeill, John H; Krassioukov, Andrei V

    2014-01-01

    Spinal cord injury (SCI) causes altered autonomic control and severe physical deconditioning that converge to drive maladaptive cardiac remodelling. We used a clinically relevant experimental model to investigate the cardio-metabolic responses to SCI and to establish whether passive hind-limb cycling elicits a cardio-protective effect. Initially, 21 male Wistar rats were evenly assigned to three groups: uninjured control (CON), T3 complete SCI (SCI) or T3 complete SCI plus passive hind-limb cycling (SCI-EX; 2 × 30 min day−1, 5 days week−1 for 4 weeks beginning 6 days post-SCI). On day 32, cardio-metabolic function was assessed using in vivo echocardiography, ex vivo working heart assessments, cardiac histology/molecular biology and blood lipid profiles. Twelve additional rats (n = 6 SCI and n = 6 SCI-EX) underwent in vivo echocardiography and basal haemodynamic assessments pre-SCI and at days 7, 14 and 32 post-SCI to track temporal cardiovascular changes. Compared with CON, SCI exhibited a rapid and sustained reduction in left ventricular dimensions and function that ultimately manifested as reduced contractility, increased myocardial collagen deposition and an up-regulation of transforming growth factor beta-1 (TGFβ1) and mothers against decapentaplegic homolog 3 (Smad3) mRNA. For SCI-EX, the initial reduction in left ventricular dimensions and function at day 7 post-SCI was completely reversed by day 32 post-SCI, and there were no differences in myocardial contractility between SCI-EX and CON. Collagen deposition was similar between SCI-EX and CON. TGFβ1 and Smad3 were down-regulated in SCI-EX. Blood lipid profiles were improved in SCI-EX versus SCI. We provide compelling novel evidence that passive hind-limb cycling prevents cardiac dysfunction and reduces cardiovascular disease risk in experimental SCI. PMID:24535438

  8. Thiol Functionalized Silica-Mixed Matrix Membranes for Silver Capture from Aqueous Solutions: Experimental Results and Modeling

    PubMed Central

    Ladhe, A. R.; Frailie, P.; Hua, D.; Darsillo, M.; Bhattacharyya, D.

    2009-01-01

    The study deals with an aqueous phase application of Mixed Matrix Membranes (MMMs) for silver ion (Ag+) capture. Silica particles were functionalized with 3-mercaptopropyltrimethoxy silane (MPTMS) to introduce free thiol (-SH) groups on the surface. The particles were used as the dispersed phase in the polysulfone or cellulose acetate polymer matrix. The membranes were prepared by the phase inversion method to create more open and interconnected porous structures suitable for liquid phase applications. The effects of the silica properties such as particle size, specific surface area, and porous/nonporous morphology on the silver ion capture capacity were studied. It was demonstrated that the membranes are capable of selectively capturing silver from a solution containing significant concentrations of other metal ions like Ca2+. The membranes were studied to quantify the dynamic capacity for silver ion capture and its dependence on residence time through the adjustment of transmembrane pressure. The thiol-Ag+ interaction was quantified with Quartz Crystal Microbalance in a continuous flow mode experiment and the observations were compared with the membrane results. One dimensional unsteady state model with overall volumetric mass transfer coefficient was developed and solved to predict the silver concentration in the liquid phase and the solid silica phase along the membrane thickness at varying time. The breakthrough data predicted using the model is comparable with the experimental observations. The study demonstrates successful application of the functionalized silica-mixed matrix membranes for selective aqueous phase Ag+ capture with high capacity at low transmembrane pressures. The technique can be easily extended to other applications by altering the functionalized groups on the silica particles. PMID:20098490

  9. IDENTIFYING MICROORGANISMS INVOLVED IN SPECIFIC IN SITU FUNCTIONS: EXPERIMENTAL DESIGN CONSIDERATIONS FOR RRNA GENE-BASED POPULATION STUDIES AND SEQUENCE-SELECTIVE PCR ASSAYS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This chapter examines experimental design considerations for a population-based approach for identifying microorganisms involved in specific in situ functions. Here, the term function is used in its broadest sense, and may refer to any number of defined biochemical, physiological or ecological pheno...

  10. In situ synthesis and surface functionalization of gold nanoparticles with curcumin and their antioxidant properties: an experimental and density functional theory investigation

    NASA Astrophysics Data System (ADS)

    Singh, Dheeraj K.; Jagannathan, Ramya; Khandelwal, Puneet; Abraham, Priya Mary; Poddar, Pankaj

    2013-02-01

    Curcumin ((1E,6E)-1,7-bis(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione) is an active component of turmeric; it is responsible for its characteristic yellow color and therapeutic potential, but its poor bioavailability remains a major challenge. In order to improve the bioavailability of curcumin, various approaches have been used. One of the possible approaches to increase the bioavailability of curcumin is its conjugation on the surface of metal nanoparticles. Therefore, in the present study, we report the binding of curcumin on the surface of gold nanoparticles (AuNPs). The AuNPs were synthesized by the direct reduction of HAuCl4 using curcumin in the aqueous phase, without the use of any other reducing agents. We found that curcumin acts both as a reducing and capping agent, stabilizing the gold sol for many months. Moreover, these curcumin-capped AuNPs also show good antioxidant activity which was confirmed by the DPPH (2,2-diphenyl-l-picrylhydrazyl) radical test. Thus, the surface functionalization of AuNPs with curcumin may pave a new way of using the curcuminoids towards possible drug delivery and therapeutics. Apart from the experimental study, a detailed quantum chemical calculation using density functional theory (DFT) has been performed, in order to investigate the formation of a complex of curcumin with Au3+ ions in different possible conformational isomeric forms. Our theoretical calculations indicate the evidence of electron transfer from curcumin into the Au center and essentially indicate that as a consequence of complexation, Au3+ ions are reduced to Au0. Our theoretical results also propose that it is the breakage of intramolecular H-bonding that probably leads to the increased availability of curcumin in the presence of gold ions and water molecules.Curcumin ((1E,6E)-1,7-bis(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione) is an active component of turmeric; it is responsible for its characteristic yellow color and therapeutic

  11. In situ synthesis and surface functionalization of gold nanoparticles with curcumin and their antioxidant properties: an experimental and density functional theory investigation.

    PubMed

    Singh, Dheeraj K; Jagannathan, Ramya; Khandelwal, Puneet; Abraham, Priya Mary; Poddar, Pankaj

    2013-03-01

    Curcumin ((1E,6E)-1,7-bis(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione) is an active component of turmeric; it is responsible for its characteristic yellow color and therapeutic potential, but its poor bioavailability remains a major challenge. In order to improve the bioavailability of curcumin, various approaches have been used. One of the possible approaches to increase the bioavailability of curcumin is its conjugation on the surface of metal nanoparticles. Therefore, in the present study, we report the binding of curcumin on the surface of gold nanoparticles (AuNPs). The AuNPs were synthesized by the direct reduction of HAuCl(4) using curcumin in the aqueous phase, without the use of any other reducing agents. We found that curcumin acts both as a reducing and capping agent, stabilizing the gold sol for many months. Moreover, these curcumin-capped AuNPs also show good antioxidant activity which was confirmed by the DPPH (2,2-diphenyl-l-picrylhydrazyl) radical test. Thus, the surface functionalization of AuNPs with curcumin may pave a new way of using the curcuminoids towards possible drug delivery and therapeutics. Apart from the experimental study, a detailed quantum chemical calculation using density functional theory (DFT) has been performed, in order to investigate the formation of a complex of curcumin with Au(3+) ions in different possible conformational isomeric forms. Our theoretical calculations indicate the evidence of electron transfer from curcumin into the Au center and essentially indicate that as a consequence of complexation, Au(3+) ions are reduced to Au(0). Our theoretical results also propose that it is the breakage of intramolecular H-bonding that probably leads to the increased availability of curcumin in the presence of gold ions and water molecules. PMID:23348618

  12. Generating information-rich high-throughput experimental materials genomes using functional clustering via multitree genetic programming and information theory.

    PubMed

    Suram, Santosh K; Haber, Joel A; Jin, Jian; Gregoire, John M

    2015-04-13

    High-throughput experimental methodologies are capable of synthesizing, screening and characterizing vast arrays of combinatorial material libraries at a very rapid rate. These methodologies strategically employ tiered screening wherein the number of compositions screened decreases as the complexity, and very often the scientific information obtained from a screening experiment, increases. The algorithm used for down-selection of samples from higher throughput screening experiment to a lower throughput screening experiment is vital in achieving information-rich experimental materials genomes. The fundamental science of material discovery lies in the establishment of composition-structure-property relationships, motivating the development of advanced down-selection algorithms which consider the information value of the selected compositions, as opposed to simply selecting the best performing compositions from a high throughput experiment. Identification of property fields (composition regions with distinct composition-property relationships) in high throughput data enables down-selection algorithms to employ advanced selection strategies, such as the selection of representative compositions from each field or selection of compositions that span the composition space of the highest performing field. Such strategies would greatly enhance the generation of data-driven discoveries. We introduce an informatics-based clustering of composition-property functional relationships using a combination of information theory and multitree genetic programming concepts for identification of property fields in a composition library. We demonstrate our approach using a complex synthetic composition-property map for a 5 at. % step ternary library consisting of four distinct property fields and finally explore the application of this methodology for capturing relationships between composition and catalytic activity for the oxygen evolution reaction for 5429 catalyst compositions in a

  13. Experimental Determination of the 1 Sigma(+) State Electric-Dipole-Moment Function of Carbon Monoxide up to a Large Internuclear Separation

    NASA Technical Reports Server (NTRS)

    Chackerian, C., Jr.; Farreng, R.; Guelachvili, G.; Rossetti, C.; Urban, W.

    1984-01-01

    Experimental intensity information is combined with numerically obtained vibrational wave functions in a nonlinear least squares fitting procedure to obtain the ground electronic state electric-dipole-moment function of carbon monoxide valid in the range of nuclear oscillation (0.87 to 1.01 A) of about the V = 38th vibrational level. Mechanical anharmonicity intensity factors, H, are computed from this function for delta V + = 1, 2, 3, with or = to 38.

  14. Functional Toll-like receptor 4 expressed in lactotrophs mediates LPS-induced proliferation in experimental pituitary hyperplasia

    SciTech Connect

    Sabatino, María Eugenia; Sosa, Liliana del Valle; Petiti, Juan Pablo; Mukdsi, Jorge Humberto; Mascanfroni, Iván Darío; Pellizas, Claudia Gabriela; Gutiérrez, Silvina; Torres, Alicia Inés; De Paul, Ana Lucía

    2013-11-15

    Toll like receptor 4 (TLR4) has been characterized for its ability to recognize bacterial endotoxin lipopolysaccharide (LPS). Considering that infections or inflammatory processes might contribute to the progression of pituitary tumors, we analyzed the TLR4 functional role by evaluating the LPS effect on lactotroph proliferation in primary cultures from experimental pituitary tumors, and examined the involvement of PI3K-Akt and NF-κB activation in this effect. In addition, the role of 17β-estradiol as a possible modulator of LPS-induced PRL cell proliferation was further investigated. In estrogen-induced hyperplasic pituitaries, LPS triggered lactotroph cell proliferation. However, endotoxin failed to increase the number of lactotrophs taking up BrdU in normal pituitaries. Moreover, incubation with anti-TLR4 antibody significantly reduced LPS-induced lactotroph proliferation, suggesting a functional role of this receptor. As a sign of TLR4 activation, an LPS challenge increased IL-6 release in normal and tumoral cells. By flow cytometry, TLR4 baseline expression was revealed at the plasma membrane of tumoral lactotrophs, without changes noted in the percentage of double PRL/TLR4 positive cells after LPS stimulus. Increases in TLR4 intracellular expression were detected as well as rises in CD14, p-Akt and NF-κB after an LPS challenge, as assessed by western blotting. The TLR4/PRL and PRL/NF-κB co-localization was also corroborated by immunofluorescence and the involvement of PI3K/Akt signaling in lactotroph proliferation and IL-6 release was revealed through the PI3K inhibitor Ly-294002. In addition, 17β-estradiol attenuated the LPS-evoked increase in tumoral lactotroph proliferation and IL-6 release. Collectively these results demonstrate the presence of functional TLR4 in lactotrophs from estrogen-induced hyperplasic pituitaries, which responded to the proliferative stimulation and IL-6 release induced by LPS through TLR4/CD14, with a contribution of the PI3K

  15. Experimental drought induces short-term changes in soil functionality and microbial community structure after fire in a Mediterranean shrubland

    NASA Astrophysics Data System (ADS)

    Hinojosa, M. B.; Parra, A.; Laudicina, V. A.; Moreno, J. M.

    2014-10-01

    Fire is a major ecosystem driver, causing significant changes in soil nutrients and microbial community structure and functionality. Post-fire soil dynamics can vary depending on rainfall patterns, although variations in response to drought are poorly known. This is particularly important in areas with poor soils and limited rainfall, like arid and semiarid ones. Furthermore, climate change projections in many such areas anticipate reduced precipitation and longer drought, together with an increase in fire severity. The effects of experimental drought and fire were studied on soils in a Mediterranean Cistus-Erica shrubland in Central Spain. A replicated (n = 4) field experiment was carried out in which four levels of rainfall pattern were implemented by means of a rain-out shelters and irrigation system. The treatments were: environmental control (natural rainfall), historical control (long-term average rainfall, 2 months drought), moderate drought (25% reduction of historical control, 5 months drought) and severe drought (45% reduction, 7 months drought). After one growing season, the plots were burned with high fire intensity, except a set of unburned plots that served as control. Soils were collected seasonally during one year and variables related to soil nutrient availability and microbial community structure and functionality were studied. Burned soils increased nutrient availability (P, N, K) with respect to unburned ones, but drought reduced such an increase in P, while it further increased N and K. Such changes in available soil nutrients were short-lived. Drought caused a further decrease of enzyme activities, carbon mineralization rate and microbial biomass. Fire decreased the relative abundance of fungi and actinomycetes. However, fire and drought caused a further reduction in fungi, with bacteria becoming relatively more abundant. Arguably, increasing drought and fires due to climate change will likely shift soil recovery after fire.

  16. The Effect of Oral Morphine on Pain-Related Brain Activation - An Experimental Functional Magnetic Resonance Imaging Study.

    PubMed

    Hansen, Tine Maria; Olesen, Anne Estrup; Graversen, Carina; Drewes, Asbjørn Mohr; Frøkjaer, Jens Brøndum

    2015-11-01

    Knowledge about cerebral mechanisms underlying pain perception and effect of analgesic drugs is important for developing methods for diagnosis and treatment of pain. The aim was to explore altered brain activation before and after morphine treatment using functional magnetic resonance imaging recorded during experimental painful heat stimulation. Functional magnetic resonance imaging data were recorded and analysed in 20 healthy volunteers (13 men and 7 women, 24.9 ± 2.6 years) in a randomized, double-blind, placebo-controlled, cross-over study. Painful stimulations were applied to the right forearm using a contact heat evoked potential stimulator (CHEPS) before and after treatment with 30 mg oral morphine and placebo. CHEPS stimulations before treatment induced activation in the anterior cingulate cortex, secondary somatosensory cortex/insula, thalamus and cerebellum (n = 16, p < 0.05). In response to morphine treatment, the spatial extent of these pain-specific areas decreased (n = 20). Reduced pain-induced activation was seen in the right insula, anterior cingulate cortex and inferior parietal cortex after morphine treatment compared to before treatment (n = 16, p < 0.05), and sensory ratings of pain perception were significantly reduced after morphine treatment (p = 0.02). No effect on pain-induced brain activation was seen after placebo treatment compared to before treatment (n = 12, p > 0.05). In conclusion, heat stimulation activated areas in the 'pain matrix' and a clinically relevant dose of orally administered morphine revealed significant changes in brain areas where opioidergic pathways are predominant. The method may be useful to investigate the mechanisms of analgesics. PMID:25924691

  17. Experimentally reduced root–microbe interactions reveal limited plasticity in functional root traits in Acer and Quercus

    PubMed Central

    Lee, Mei-Ho; Comas, Louise H.; Callahan, Hilary S.

    2014-01-01

    Background and Aims Interactions between roots and soil microbes are critical components of below-ground ecology. It is essential to quantify the magnitude of root trait variation both among and within species, including variation due to plasticity. In addition to contextualizing the magnitude of plasticity relative to differences between species, studies of plasticity can ascertain if plasticity is predictable and whether an environmental factor elicits changes in traits that are functionally advantageous. Methods To compare functional traits and trait plasticities in fine root tissues with natural and reduced levels of colonization by microbial symbionts, trimmed and surface-sterilized root segments of 2-year-old Acer rubrum and Quercus rubra seedlings were manipulated. Segments were then replanted into satellite pots filled with control or heat-treated soil, both originally derived from a natural forest. Mycorrhizal colonization was near zero in roots grown in heat-treated soil; roots grown in control soil matched the higher colonization levels observed in unmanipulated root samples collected from field locations. Key Results Between-treatment comparisons revealed negligible plasticity for root diameter, branching intensity and nitrogen concentration across both species. Roots from treated soils had decreased tissue density (approx. 10–20 %) and increased specific root length (approx. 10–30 %). In contrast, species differences were significant and greater than treatment effects in traits other than tissue density. Interspecific trait differences were also significant in field samples, which generally resembled greenhouse samples. Conclusions The combination of experimental and field approaches was useful for contextualizing trait plasticity in comparison with inter- and intra-specific trait variation. Findings that root traits are largely species dependent, with the exception of root tissue density, are discussed in the context of current literature on root

  18. Recent progresses in the experimental methods and evaluation strategies of transporter functions for the prediction of the pharmacokinetics in humans.

    PubMed

    Kitamura, Satoshi; Maeda, Kazuya; Sugiyama, Yuichi

    2008-06-01

    Establishing the methods for the effective screening of compounds with optimal pharmacokinetic properties is of great importance to many scientists working in new drug discovery and development. This review deals with the methods by which in vivo pharmacokinetics in humans can be predicted from in vitro studies and from in vivo animal experiments. Direct extrapolation from animal studies to human pharmacokinetics is generally difficult because of species differences in the function of molecules involved in drug metabolism and transport. To overcome this problem, a "scaling factor," which relates in vivo animal studies with in vitro experiments, is often used for the accurate prediction. Several experimental systems for the functional analyses of membrane transporters have been developed and many reports have revealed that various transporters clearly govern the tissue dispositions of drugs in humans. This review covers the impact of membrane transporters on the pharmacokinetics, control of elimination pathways, and toxicity. Indeed, by utilizing transporter-deficient animals, some studies have clarified the importance of transporters in various types of tissue-specific toxicity. Transporter-mediated drug-drug interactions are one of the most important issues in clinical situation because some reports suggested that severe clinical incidents are caused by the inhibition of transporter-mediated uptake and efflux in clearance organs (liver and kidney) and at several barriers. The review also focuses on the clinical significance of genetic polymorphisms of transporters, as these can influence the plasma and tissue concentrations of some drugs. Finally, integrated information is presented based on multiple in vitro studies, including those on transporters. This should enable the prediction of the outcomes of drug exposure in cells, tissues, and individual organisms. PMID:18536908

  19. The Effects of Tumstatin on Vascularity, Airway Inflammation and Lung Function in an Experimental Sheep Model of Chronic Asthma.

    PubMed

    Van der Velden, Joanne; Harkness, Louise M; Barker, Donna M; Barcham, Garry J; Ugalde, Cathryn L; Koumoundouros, Emmanuel; Bao, Heidi; Organ, Louise A; Tokanovic, Ana; Burgess, Janette K; Snibson, Kenneth J

    2016-01-01

    Tumstatin, a protein fragment of the alpha-3 chain of Collagen IV, is known to be significantly reduced in the airways of asthmatics. Further, there is evidence that suggests a link between the relatively low level of tumstatin and the induction of angiogenesis and inflammation in allergic airway disease. Here, we show that the intra-segmental administration of tumstatin can impede the development of vascular remodelling and allergic inflammatory responses that are induced in a segmental challenge model of experimental asthma in sheep. In particular, the administration of tumstatin to lung segments chronically exposed to house dust mite (HDM) resulted in a significant reduction of airway small blood vessels in the diameter range 10(+)-20 μm compared to controls. In tumstatin treated lung segments after HDM challenge, the number of eosinophils was significantly reduced in parenchymal and airway wall tissues, as well as in the bronchoalveolar lavage fluid. The expression of VEGF in airway smooth muscle was also significantly reduced in tumstatin-treated segments compared to control saline-treated segments. Allergic lung function responses were not attenuated by tumstatin administration in this model. The data are consistent with the concept that tumstatin can act to suppress vascular remodelling and inflammation in allergic airway disease. PMID:27199164

  20. Functional adaptation of crustacean exoskeletal elements through structural and compositional diversity: a combined experimental and theoretical study.

    PubMed

    Fabritius, Helge-Otto; Ziegler, Andreas; Friák, Martin; Nikolov, Svetoslav; Huber, Julia; Seidl, Bastian H M; Ruangchai, Sukhum; Alagboso, Francisca I; Karsten, Simone; Lu, Jin; Janus, Anna M; Petrov, Michal; Zhu, Li-Fang; Hemzalová, Pavlína; Hild, Sabine; Raabe, Dierk; Neugebauer, Jörg

    2016-01-01

    The crustacean cuticle is a composite material that covers the whole animal and forms the continuous exoskeleton. Nano-fibers composed of chitin and protein molecules form most of the organic matrix of the cuticle that, at the macroscale, is organized in up to eight hierarchical levels. At least two of them, the exo- and endocuticle, contain a mineral phase of mainly Mg-calcite, amorphous calcium carbonate and phosphate. The high number of hierarchical levels and the compositional diversity provide a high degree of freedom for varying the physical, in particular mechanical, properties of the material. This makes the cuticle a versatile material ideally suited to form a variety of skeletal elements that are adapted to different functions and the eco-physiological strains of individual species. This review presents our recent analytical, experimental and theoretical studies on the cuticle, summarising at which hierarchical levels structure and composition are modified to achieve the required physical properties. We describe our multi-scale hierarchical modeling approach based on the results from these studies, aiming at systematically predicting the structure-composition-property relations of cuticle composites from the molecular level to the macro-scale. This modeling approach provides a tool to facilitate the development of optimized biomimetic materials within a knowledge-based design approach. PMID:27609556

  1. Experimental Strategies for Functional Annotation and Metabolism Discovery: Targeted Screening of Solute Binding Proteins and Unbiased Panning of Metabolomes

    PubMed Central

    2015-01-01

    The rate at which genome sequencing data is accruing demands enhanced methods for functional annotation and metabolism discovery. Solute binding proteins (SBPs) facilitate the transport of the first reactant in a metabolic pathway, thereby constraining the regions of chemical space and the chemistries that must be considered for pathway reconstruction. We describe high-throughput protein production and differential scanning fluorimetry platforms, which enabled the screening of 158 SBPs against a 189 component library specifically tailored for this class of proteins. Like all screening efforts, this approach is limited by the practical constraints imposed by construction of the library, i.e., we can study only those metabolites that are known to exist and which can be made in sufficient quantities for experimentation. To move beyond these inherent limitations, we illustrate the promise of crystallographic- and mass spectrometric-based approaches for the unbiased use of entire metabolomes as screening libraries. Together, our approaches identified 40 new SBP ligands, generated experiment-based annotations for 2084 SBPs in 71 isofunctional clusters, and defined numerous metabolic pathways, including novel catabolic pathways for the utilization of ethanolamine as sole nitrogen source and the use of d-Ala-d-Ala as sole carbon source. These efforts begin to define an integrated strategy for realizing the full value of amassing genome sequence data. PMID:25540822

  2. Scaffold microstructure effects on functional and mechanical performance: Integration of theoretical and experimental approaches for bone tissue engineering applications.

    PubMed

    Cavo, Marta; Scaglione, Silvia

    2016-11-01

    The really nontrivial goal of tissue engineering is combining all scaffold micro-architectural features, affecting both fluid-dynamical and mechanical performance, to obtain a fully functional implant. In this work we identified an optimal geometrical pattern for bone tissue engineering applications, best balancing several graft needs which correspond to competing design goals. In particular, we investigated the occurred changes in graft behavior by varying pore size (300μm, 600μm, 900μm), interpore distance (equal to pore size or 300μm fixed) and pores interconnection (absent, 45°-oriented, 90°-oriented). Mathematical considerations and Computational Fluid Dynamics (CFD) tools, here combined in a complete theoretical model, were carried out to this aim. Poly-lactic acid (PLA) based samples were realized by 3D printing, basing on the modeled architectures. A collagen (COL) coating was also realized on grafts surface and the interaction between PLA and COL, besides the protein contribution to graft bioactivity, was evaluated. Scaffolds were extensively characterized; human articular cells were used to test their biocompatibility and to evaluate the theoretical model predictions. Grafts fulfilled both the chemical and physical requirements. Finally, a good agreement was found between the theoretical model predictions and the experimental data, making these prototypes good candidates for bone graft replacements. PMID:27524090

  3. Novel Function of Extracellular Matrix Protein 1 in Suppressing Th17 Cell Development in Experimental Autoimmune Encephalomyelitis.

    PubMed

    Su, Pan; Chen, Sheng; Zheng, Yu Han; Zhou, Hai Yan; Yan, Cheng Hua; Yu, Fang; Zhang, Ya Guang; He, Lan; Zhang, Yuan; Wang, Yanming; Wu, Lei; Wu, Xiaoai; Yu, Bingke; Ma, Li Yan; Yang, Zhiru; Wang, Jianhua; Zhao, Guixian; Zhu, Jinfang; Wu, Zhi-Ying; Sun, Bing

    2016-08-15

    Multiple sclerosis (MS) is a chronic inflammatory disease of the CNS characterized by demyelination and axonal damage. Experimental autoimmune encephalomyelitis (EAE) is a well-established animal model for human MS. Although Th17 cells are important for disease induction, Th2 cells are inhibitory in this process. In this article, we report the effect of a Th2 cell product, extracellular matrix protein 1 (ECM1), on the differentiation of Th17 cells and the development of EAE. Our results demonstrated that ECM1 administration from day 1 to day 7 following the EAE induction could ameliorate the Th17 cell responses and EAE development in vivo. Further study of the mechanism revealed that ECM1 could interact with αv integrin on dendritic cells and block the αv integrin-mediated activation of latent TGF-β, resulting in an inhibition of Th17 cell differentiation at an early stage of EAE induction. Furthermore, overexpression of ECM1 in vivo significantly inhibited the Th17 cell response and EAE induction in ECM1 transgenic mice. Overall, our work has identified a novel function of ECM1 in inhibiting Th17 cell differentiation in the EAE model, suggesting that ECM1 may have the potential to be used in clinical applications for understanding the pathogenesis of MS and its diagnosis. PMID:27316685

  4. The Effects of Tumstatin on Vascularity, Airway Inflammation and Lung Function in an Experimental Sheep Model of Chronic Asthma

    PubMed Central

    Van der Velden, Joanne; Harkness, Louise M.; Barker, Donna M.; Barcham, Garry J.; Ugalde, Cathryn L.; Koumoundouros, Emmanuel; Bao, Heidi; Organ, Louise A.; Tokanovic, Ana; Burgess, Janette K.; Snibson, Kenneth J.

    2016-01-01

    Tumstatin, a protein fragment of the alpha-3 chain of Collagen IV, is known to be significantly reduced in the airways of asthmatics. Further, there is evidence that suggests a link between the relatively low level of tumstatin and the induction of angiogenesis and inflammation in allergic airway disease. Here, we show that the intra-segmental administration of tumstatin can impede the development of vascular remodelling and allergic inflammatory responses that are induced in a segmental challenge model of experimental asthma in sheep. In particular, the administration of tumstatin to lung segments chronically exposed to house dust mite (HDM) resulted in a significant reduction of airway small blood vessels in the diameter range 10+–20 μm compared to controls. In tumstatin treated lung segments after HDM challenge, the number of eosinophils was significantly reduced in parenchymal and airway wall tissues, as well as in the bronchoalveolar lavage fluid. The expression of VEGF in airway smooth muscle was also significantly reduced in tumstatin-treated segments compared to control saline-treated segments. Allergic lung function responses were not attenuated by tumstatin administration in this model. The data are consistent with the concept that tumstatin can act to suppress vascular remodelling and inflammation in allergic airway disease. PMID:27199164

  5. Optimal electron irradiation as a tool for functionalization of MoS{sub 2}: Theoretical and experimental investigation

    SciTech Connect

    Karmakar, Debjani Padma, N.; Ghosh, M.; Kaur, M.; Chandrasekhar Rao, T. V.; Halder, Rumu; Abraham, Geogy; Vaibhav, K.; Bhattacharya, D.

    2015-04-07

    We demonstrate the utility of electron irradiation as a tool to enhance device functionality of graphene-analogous MoS{sub 2}. With the help of first-principles based calculations, vacancy-induced changes of various electronic properties are shown to be a combined result of crystal-field modification and spin-orbital coupling. A comparative theoretical study of various possible vacancy configurations both in bulk and monolayer MoS{sub 2} and related changes in their respective band-structures help us to explain plausible irradiation induced effects. Experimentally, various structural forms of MoS{sub 2} in bulk, few layered flakes, and nanocrystals are observed to exhibit important modification of their magnetic, transport, and vibrational properties, following low doses of electron irradiation. While irradiated single crystals and nanocrystals show an enhanced magnetization, transport properties of few-layered devices show a significant increase in their conductivity, which can be very useful for fabrication of electronic devices. Our theoretical calculations reveal that this increase in n-type conductivity and magnetization can be correlated with the presence of sulfur and molybdenum vacancies.

  6. Density functional investigation of photo induced Intramolecular Proton Transfer (IPT) in Indole-7-carboxaldehyde and its experimental verification

    NASA Astrophysics Data System (ADS)

    Singla, Nidhi; Chowdhury, Papia

    2013-08-01

    A detail theoretical study has been performed using Density functional theory (DFT) and Time dependent DFT (TDDFT) to investigate the Intramolecular Proton Transfer (IPT) mechanism in Indole-7-carboxaldehyde (I7C) from its normal (I*) to zwitterion (II*) form. B3LYP/6-311++G (d, p) basis set has been used to obtain structural parameters and relative energies in the ground state (S0) and excited state (S1). Atoms in Molecules (AIMs), Mulliken and Natural bond orbitals (NBOs) analysis proves the existence of intramolecular hydrogen bonding (IHB). The electron density (ρ) at Bond critical points (BCPs) on a hydrogen bridge (N15sbnd H12⋯O18) certify IHB and possibility of IPT from acidic (N15sbnd H12) to basic (lbond2 C16dbnd O18) group and creation of II*. Transition state (TS) with dual minima in the Potential energy surface (PES) confirms the I* → TS → II* transition due to excited state Intramolecular Proton Transfer (ESIPT). Photo-physical pathway from I* → II* agrees well with computed/experimental emission peaks.

  7. An experimental and theoretical study of furan decomposition on palladium(111) using scanning tunneling microscopy and density functional theory

    NASA Astrophysics Data System (ADS)

    Loui, Albert

    Furan (C4H4O) has been investigated as a prototypical model species in heterogeneous catalyst studies, under both ultrahigh vacuum and industrial conditions. The adsorption and decomposition of furan on Pd(111) has been previously studied with thermal desorption and vibrational spectroscopies; these studies support intact adsorption of the heterocycle below 280 K, with dissociation to H, CO, and a C3H3 species for temperatures between 280 to 320 K. The hydrocarbon moiety is adsorbed through ˜400 K, whereupon complete dehydrogenation to a carbidic overlayer is onset. Using scanning tunneling microscopy (STM), I have imaged the intactly-adsorbed molecules in UHV at temperatures below 280 K; these experiments have revealed strikingly different adsorption behaviors on narrow and wide terraces of vicinal Pd(111). For higher temperatures (up to 415 K), STM has been used to probe C4H4O dissociation to form the C3H3 species. These data exhibit structure-specific properties, most prominently a preferential adsorption of furan at upper step edge sites and an apparent depletion of such sites after the reaction has gone to completion. Such observations are consistent with previous experimental and theoretical studies of molecular adsorption, diffusion, and reaction on vicinal, low-Miller-index transition metal surfaces. The structure and energetics of furan chemisorption on Pd(111) are explored with surface electronic calculations based on ab initio density functional theory (DFT). These calculations reveal two types of stable adsorption configurations, located in positions of high symmetry relative to hollow sites on the close-packed surface. The chemisorption strengths in these geometries are closely correlated to the relaxed structures of both the adsorbate and the substrate, and involve a partial loss of aromaticity in the furan molecule. Calculated STM images of the stable furan configurations on the Pd(111) surface are also presented; these plots are generated from

  8. Experimental model of toxin-induced subclinical mastitis and its effect on disruption of follicular function in cows.

    PubMed

    Furman, Ori; Leitner, Gabriel; Roth, Zvi; Lavon, Yaniv; Jacoby, Shamay; Wolfenson, David

    2014-11-01

    (but not immediate) decrease to 51% and 62% in follicular estradiol concentrations in G- affected group and G+ affected group was detected relative to controls (P < 0.05). The nonaffected G+ subgroup did not differ from its control counterparts. Based on the current experimental model, subclinical IMI induced by G+ or G- toxin disrupts follicular functions, and it seems that the ovarian pool of early antral follicles is susceptible to subclinical mastitis. PMID:25212394

  9. What is New and Innovative in Emergency Neurosurgery? Emerging Diagnostic Technologies Provide Better Care and Influence Outcome: A Specialist Review

    PubMed Central

    Zisakis, Athanasios K.; Exadaktylos, Aristomenis

    2013-01-01

    The development of emergency medical services and especially neurosurgical emergencies during recent decades has necessitated the development of novel tools. Although the gadgets that the neurosurgeon uses today in emergencies give him important help in diagnosis and treatment, we still need new technology, which has rapidly developed. This review presents the latest diagnostic tools, which offer precious help in everyday emergency neurosurgery practice. New ultrasound devices make the diagnosis of haematomas easier. In stroke, the introduction of noninvasive new gadgets aims to provide better treatment to the patient. Finally, the entire development of computed tomography and progress in radiology have resulted in innovative CT scans and angiographic devices that advance the diagnosis, treatment, and outcome of the patent. The pressure on physicians to be quick and effective and to avoid any misjudgement of the patient has been transferred to the technology, with the emphasis on developing new systems that will provide our patients with a better outcome and quality of life. PMID:24349786

  10. From anesthetic sponge to nonsinking skull perforator, unitary work neurosurgery in the ancient Arabic and Islamic world.

    PubMed

    Najjar, Jalal

    2010-05-01

    During the Middle Ages, the work of Middle Eastern physicians such as Avicenna, Albucasis, and Rhazes was of paramount importance in guarding the knowledge that had been accumulated throughout history, particularly the contributions of Greek and Roman scholars, and it is well known that the Arabic versions of all of the works by Hippocrates and Galen by Islamic and Arabic scholars are the only copies that have survived until now. In addition to preserving this wealth of knowledge, these Middle Eastern scholars made significant contributions of their own to both medicine and neurosurgery. Many points regarding ancient Arabic and Islamic science need to be discussed and clarified, such as cadaver dissections, anatomic studies, neurosurgical practice and instruments, Arabic translations of Hippocratic and other works, and the influence of the Islamic civilization on Western civilization, especially the Renaissance. PMID:20920948

  11. Approach-specific multi-grid anatomical modeling for neurosurgery simulation with public-domain and open-source software

    PubMed Central

    Audette, Michel A.; Rivière, Denis; Law, Charles; Ibanez, Luis; Aylward, Stephen R; Finet, Julien; Wu, Xunlei; Ewend, Matthew G.

    2011-01-01

    We present on-going work on multi-resolution sulcal-separable meshing for approach-specific neurosurgery simulation, in conjunction multi-grid and Total Lagrangian Explicit Dynamics finite elements. Conflicting requirements of interactive nonlinear finite elements and small structures lead to a multi-grid framework. Implications for meshing are explicit control over resolution, and prior knowledge of the intended neurosurgical approach and intended path. This information is used to define a subvolume of clinical interest, within some distance of the path and the target pathology. Restricted to this subvolume are a tetrahedralization of finer resolution, the representation of critical tissues, and sulcal separability constraint for all mesh levels. PMID:21666884

  12. Automatic ultrasound-MRI registration for neurosurgery using the 2D and 3D LC(2) Metric.

    PubMed

    Fuerst, Bernhard; Wein, Wolfgang; Müller, Markus; Navab, Nassir

    2014-12-01

    To enable image guided neurosurgery, the alignment of pre-interventional magnetic resonance imaging (MRI) and intra-operative ultrasound (US) is commonly required. We present two automatic image registration algorithms using the similarity measure Linear Correlation of Linear Combination (LC(2)) to align either freehand US slices or US volumes with MRI images. Both approaches allow an automatic and robust registration, while the three dimensional method yields a significantly improved percentage of optimally aligned registrations for randomly chosen clinically relevant initializations. This study presents a detailed description of the methodology and an extensive evaluation showing an accuracy of 2.51mm, precision of 0.85mm and capture range of 15mm (>95% convergence) using 14 clinical neurosurgical cases. PMID:24842859

  13. Functional Responses of Bacterioplankton Diversity and Metabolism to Experimental Bottom-Up and Top-Down Forcings.

    PubMed

    Pradeep Ram, A S; Chaibi-Slouma, S; Keshri, J; Colombet, J; Sime-Ngando, T

    2016-08-01

    We conducted an experimental approach using microcosms to simultaneously examine the functional response of natural freshwater bacterial assemblages to the impact of resources (nutrients) and top-down factors (viruses and grazers) on bacterial physiological state and their community structure. Addition of organic and inorganic nutrients led to the proliferation of high nucleic acid content bacterial cells accompanied by high bacterial growth efficiency (considered as proxy of bacterial carbon metabolism) estimates, suggesting that this subgroup represented the most active fraction of bacterial community and had a high capacity to incorporate carbon into its biomass. However, their rapid growth induced the pressure of viral lytic infection which led to their lysis toward the end of the experiment. In microcosms with flagellates plus viruses, and with viruses alone, the selective removal of metabolically active high nucleic acid cells through viral lysis benefitted the less active low nucleic acid content cells, perhaps via the use of lysis products for its growth and survival. Changes in bacterial physiological state in microcosms were reflected in their community structure which was examined using 16S ribosomal RNA (rRNA) gene sequencing by Illumina's Miseq platform. Chao estimator and Shannon diversity index values suggested that bacterial species richness was highest in the presence of both the top-down factors, indicating a tighter control of bacterioplankton dominants within a relatively stable bacterial community. The increase in bacterial metabolism with nutrient addition followed by subsequent lysis of bacterial dominants indicate that both resources and top-down factors work in concert for the sustenance of stable bacterial communities. PMID:27179523

  14. Cancer treatment and gonadal function: experimental and established strategies for fertility preservation in children and young adults.

    PubMed

    Anderson, Richard A; Mitchell, Rod T; Kelsey, Thomas W; Spears, Norah; Telfer, Evelyn E; Wallace, W Hamish B

    2015-07-01

    Preservation of gonadal function is an important priority for the long-term health of cancer survivors of both sexes and all ages at treatment. Loss of opportunity for fertility is a prime concern in both male and female cancer survivors, but endocrine effects of gonadal damage are likewise central to long-term health and wellbeing. Some fertility preservation techniques, such as semen and embryo cryopreservation, are established and successful in adults, and development of oocyte vitrification has greatly improved the potential to cryopreserve unfertilised oocytes. Despite being recommended for all pubertal male patients, sperm banking is not universally practised in paediatric oncology centres, and very few adolescent-friendly facilities exist. All approaches to fertility preservation have specific challenges in children and teenagers, including ethical, practical, and scientific issues. For young women, cryopreservation of ovarian cortical tissue with later replacement has resulted in at least 40 livebirths, but is still regarded as experimental in most countries. For prepubertal boys, testicular biopsy cryopreservation is offered in some centres, but how that tissue might be used in the future is unclear, and so far no evidence suggests that fertility can be restored. For both sexes, these approaches involve an invasive procedure and have an uncertain risk of tissue contamination in haematological and other malignancies. Decision making for all these approaches needs assessment of the individual's risk of fertility loss, and is made at a time of emotional distress. Development of this specialty needs better provision of information for patients and their medical teams, and improvements in service provision, to match technical and scientific advances. PMID:25873571

  15. Exogenous connexin43-expressing autologous skeletal myoblasts ameliorate mechanical function and electrical activity of the rabbit heart after experimental infarction

    PubMed Central

    Antanavičiūtė, Ieva; Ereminienė, Eglė; Vysockas, Vaidas; Račkauskas, Mindaugas; Skipskis, Vilius; Rysevaitė, Kristina; Treinys, Rimantas; Benetis, Rimantas; Jurevičius, Jonas; Skeberdis, Vytenis A

    2015-01-01

    Acute myocardial infarction is one of the major causes of mortality worldwide. For regeneration of the rabbit heart after experimentally induced infarction we used autologous skeletal myoblasts (SMs) due to their high proliferative potential, resistance to ischaemia and absence of immunological and ethical concerns. The cells were characterized with muscle-specific and myogenic markers. Cell transplantation was performed by injection of cell suspension (0.5 ml) containing approximately 6 million myoblasts into the infarction zone. The animals were divided into four groups: (i) no injection; (ii) sham injected; (iii) injected with wild-type SMs; and (iv) injected with SMs expressing connexin43 fused with green fluorescent protein (Cx43EGFP). Left ventricular ejection fraction (LVEF) was evaluated by 2D echocardiography in vivo before infarction, when myocardium has stabilized after infarction, and 3 months after infarction. Electrical activity in the healthy and infarction zones of the heart was examined ex vivo in Langendorff-perfused hearts by optical mapping using di-4-ANEPPS, a potential sensitive fluorescent dye. We demonstrate that SMs in the coculture can couple electrically not only to abutted but also to remote acutely isolated allogenic cardiac myocytes through membranous tunnelling tubes. The beneficial effect of cellular therapy on LVEF and electrical activity was observed in the group of animals injected with Cx43EGFP-expressing SMs. L-type Ca2+ current amplitude was approximately fivefold smaller in the isolated SMs compared to healthy myocytes suggesting that limited recovery of LVEF may be related to inadequate expression or function of L-type Ca2+ channels in transplanted differentiating SMs. PMID:25529770

  16. Comparison of the various methods for the direct calculation of the transmission functions of the 15-micron CO2 band with experimental data

    NASA Technical Reports Server (NTRS)

    1978-01-01

    Various methods for calculating the transmission functions of the 15 micron CO2 band are described. The results of these methods are compared with laboratory measurements. It is found that program P4 provides the best agreement with experimental results on the average.

  17. CALCULATED MOLECULAR STRUCTURES AND POTENTIAL ENERGY FUNCTIONS OF PAHS WITH METHYL CROWDING IN THE BAY REGION AND THEIR METABOLITES: COMPARISON TO EXPERIMENTAL STRUCTURES

    EPA Science Inventory

    Calculated molecular structures and potential energy functions ofP AHs with methyl crowding in the bay region and their metabolites: Comparison to experimental structures

    PAHs with methyl group substitution near a bay region represent a class of chemicals associated with ...

  18. CALCULATED MOLECULAR STRUCTURES AND POTENTIAL ENERGY FUNCTIONS OF PAHS WITH METHYL CROWDING IN THE BAY REGION AND THEIR METABOLITES: COMPARISON TO EXPERIMENTAL STRUCTURES

    EPA Science Inventory

    Abstract Title: Calculated molecular structures and potential energy functions of P AHs with methyl crowding in the bay region and their metabolites: Comparison to experimental structures.

    Abstract:
    PAHs with methyl group substitution near a bay region represent a cl...

  19. Effect of tumor resection on the characteristics of functional brain networks

    NASA Astrophysics Data System (ADS)

    Wang, H.; Douw, L.; Hernández, J. M.; Reijneveld, J. C.; Stam, C. J.; van Mieghem, P.

    2010-08-01

    Brain functioning such as cognitive performance depends on the functional interactions between brain areas, namely, the functional brain networks. The functional brain networks of a group of patients with brain tumors are measured before and after tumor resection. In this work, we perform a weighted network analysis to understand the effect of neurosurgery on the characteristics of functional brain networks. Statistically significant changes in network features have been discovered in the beta (13-30 Hz) band after neurosurgery: the link weight correlation around nodes and within triangles increases which implies improvement in local efficiency of information transfer and robustness; the clustering of high link weights in a subgraph becomes stronger, which enhances the global transport capability; and the decrease in the synchronization or virus spreading threshold, revealed by the increase in the largest eigenvalue of the adjacency matrix, which suggests again the improvement of information dissemination.

  20. Effect of tumor resection on the characteristics of functional brain networks.

    PubMed

    Wang, H; Douw, L; Hernández, J M; Reijneveld, J C; Stam, C J; Van Mieghem, P

    2010-08-01

    Brain functioning such as cognitive performance depends on the functional interactions between brain areas, namely, the functional brain networks. The functional brain networks of a group of patients with brain tumors are measured before and after tumor resection. In this work, we perform a weighted network analysis to understand the effect of neurosurgery on the characteristics of functional brain networks. Statistically significant changes in network features have been discovered in the beta (13-30 Hz) band after neurosurgery: the link weight correlation around nodes and within triangles increases which implies improvement in local efficiency of information transfer and robustness; the clustering of high link weights in a subgraph becomes stronger, which enhances the global transport capability; and the decrease in the synchronization or virus spreading threshold, revealed by the increase in the largest eigenvalue of the adjacency matrix, which suggests again the improvement of information dissemination. PMID:20866854

  1. Experimental and numerical tribological studies of a boundary lubricant functionalized poro-viscoelastic PVA hydrogel in normal contact and sliding.

    PubMed

    Blum, Michelle M; Ovaert, Timothy C

    2012-10-01

    Hydrogels are a cross-linked network of polymers swollen with liquid and have the potential to be used as a synthetic replacement for local defects in load bearing tissues such as articular cartilage. Hydrogels display viscoelastic time dependent behavior, therefore experimental analysis of stresses at the surface and within the gel is difficult to perform. A three-dimensional model of a hydrogel was developed in the commercial finite element software ABAQUS™, implementing a poro-viscoelastic constitutive model along with a contact-dependent flow state and friction conditions. Water content measurements, sliding, and indentation experiments were performed on neat polyvinyl alcohol (PVA), and on low friction boundary lubricant functionalized (BLF-PVA) hydrogels, both manufactured by freeze-thaw processes. Modulus results from the indentation experiments and coefficient of friction values from the sliding experiments were used as material property inputs to the model, while water content was used to calculate initial flow conditions. Tangential force and normal displacement data from a three-dimensional simulation of sliding were compared with the experiments. The tangential force patterns indicated important similarities with the fabricated hydrogels that included an initially high force value due to time dependent deformation followed by a decrease in a stabile value. A similar trend was observed with the normal displacement. These comparisons rendered the model suitable as a representation and were used to analyze the development and propagation of stresses in the immediate surface region. The results showed that in a three-dimensional stress field during sliding, the maximum stress shifted to the surface and rotated closer to the leading edge of contact. This occurred because the stress field becomes dominated by an amplified compressive stress at the leading edge due to the biphasic viscoelastic response of the material during sliding. Also, the complex multi

  2. Essentials of research methods in neurosurgery and allied sciences for research, appraisal and application of scientific information to patient care (Part I).

    PubMed

    Esene, Ignatius N; El-Shehaby, Amr M; Baeesa, Saleh S

    2016-04-01

    Every neurosurgeon ought to be acquainted with the basics of research methods to enhance the comprehension of the research process and critical appraisal procedures of a scientific write-up. This in turn will ensure the appropriate application of scientific knowledge to patient care. Recent publications reveal that a significant proportion of articles published in neurosurgery are mislabeled with dire consequences on the sorting and indexing of evidence. Furthermore, many clinicians report that they feel unqualified to read the medical literature critically hence, it is for this reason that we conducted this review. Herein, we present a simple algorithm to facilitate the comprehension of research methods, as well as elucidate on the anatomy of common study designs in neurosurgery. Illustrative examples are provided when necessary. Understanding research methods and the critical analysis of published reports of clinical investigation is a fundamental skill of the physician to enable the incorporation of new clinical knowledge to practice. PMID:27094519

  3. Factors Affecting The Experimental Line Spread Function (Lsf) Measurement And Modulation Transfer Function (Mtf) Calculation Including Deviation In Characteristic Curve Shape

    NASA Astrophysics Data System (ADS)

    Dahle, Marcia E.; Haus, Arthur G.

    1980-08-01

    The major potential errors in the slit method measurement of the line spread function (LSF) and the modu-lation transfer function (MTF) of radiographic screen-film systems are reviewed. These errors are compared with the potential error introduced in the LSF due to an erroneous representation of the characteristic curve (sensitometric data). If a deviation in the sensitometric data results in a lower average gradient of the characteristic curve, the MTF will show higher resolution capabilities.