Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Bionics”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 37 records · Page 2Linked to original sources
PubMed2004

Bionic epidural stimulation restores arterial pressure regulation during orthostasis.

A bionic baroreflex system (BBS) is a computer-assisted intelligent feedback system to control arterial pressure (AP) for the treatment of baroreflex failure. To apply this system clinically, an appropriate efferent neural (sympathetic vasomotor) interface has to be explored. We examined whether the spinal cord is a candidate site for such interface. In six anesthetized and baroreflex-deafferentiated cats, a multielectrode catheter was inserted into the epidural space to deliver epidural spinal cord stimulation (ESCS). Stepwise changes in ESCS rate revealed a linear correlation between ESCS rate and AP for ESCS rates of 2 pulses/s and above (r2, 0.876-0.979; slope, 14.3 +/- 5.8 mmHg.pulses(-1).s; pressure axis intercept, 35.7 +/- 25.9 mmHg). Random changes in ESCS rate with a white noise sequence revealed dynamic transfer function of peripheral effectors. The transfer function resembled a second-order, low-pass filter with a lag time (gain, 16.7 +/- 8.3 mmHg.pulses(-1).s; natural frequency, 0.022 +/- 0.007 Hz; damping coefficient, 2.40 +/- 1.07; lag time, 1.06 +/- 0.41 s). On the basis of the transfer function, we designed an artificial vasomotor center to attenuate hypotension. We evaluated the performance of the BBS against hypotension induced by 60 degrees head-up tilt. In the cats with baroreflex failure, head-up tilt dropped AP by 37 +/- 5 mmHg in 5 s and 59 +/- 11 mmHg in 30 s. BBS with optimized feedback parameters attenuated hypotension to 21 +/- 2 mmHg in 5 s (P < 0.05) and 8 +/- 4 mmHg in 30 s (P < 0.05). These results indicate that ESCS-mediated BBS prevents orthostatic hypotension. Because epidural stimulation is a clinically feasible procedure, this BBS can be applied clinically to combat hypotension associated with various pathophysiologies.

Animals↗
PubMed2006

Micromechanical resonator array for an implantable bionic ear.

In this paper we report on a multi-resonant transducer that may be used to replace a traditional speech processor in cochlear implant applications. The transducer, made from an array of micro-machined polymer resonators, is capable of passively splitting sound into its frequency sub-bands without the need for analog-to-digital conversion and subsequent digital processing. Since all bands are mechanically filtered in parallel, there is low latency in the output signals. The simplicity of the device, high channel capability, low power requirements, and small form factor (less than 1 cm) make it a good candidate for a completely implantable bionic ear device.

Algorithms↗
PubMed1999

Novel therapeutic strategy against central baroreflex failure: a bionic baroreflex system.

BACKGROUND: Central baroreflex failure in Shy-Drager syndrome and traumatic spinal cord injuries results in severe orthostatic hypotension and often confines the patient to the bed. We proposed a novel therapeutic strategy against central baroreflex failure: implementation of an artificial feedback control system able automatically to regulate sympathetic vasomotor tone, that is, a bionic baroreflex system (BBS). With the use of a rat model of central baroreflex failure, we developed the BBS and tested its efficacy. METHODS AND RESULTS: Our prototype BBS for the rat consisted of a pressure sensor placed into the aortic arch, stimulation electrodes implanted into the greater splanchnic nerve, and a computer-driven neural stimulator. By a white noise approach for system identification, we first estimated the dynamic properties underlying the normal baroreflex control of systemic arterial pressure (SAP) and then determined how the BBS computer should operate in real time as the artificial vasomotor center to mimic the dynamic properties of the native baroreflex. The open-loop transfer function of the artificial vasomotor center was identified as a high-pass filter with a corner frequency of 0.1 Hz. We evaluated the performance of the BBS in response to rapid-progressive hypotension secondary to sudden sympathetic withdrawal evoked by the local imposition of a pressure step on carotid sinus baroreceptors in 16 anesthetized rats. Without the BBS, SAP rapidly fell by 49+/-8 mm Hg in 10 seconds. With the BBS placed on-line with real-time execution, the SAP fall was suppressed by 22+/-6 mm Hg at the nadir and by 16+/-5 mm Hg at the plateau. These effects were statistically indistinguishable from those of the native baroreflex system. CONCLUSIONS: These results suggest the feasibility of a BBS approach for central baroreflex failure.

Animals↗
PubMed2006

Artificial baroreflex: clinical application of a bionic baroreflex system.

BACKGROUND: We proposed a novel therapeutic strategy against central baroreflex failure: implementation of an artificial baroreflex system to automatically regulate sympathetic vasomotor tone, ie, a bionic baroreflex system (BBS), and we tested its efficacy in a model of sudden hypotension during surgery. METHODS AND RESULTS: The BBS consisted of a computer-controlled negative-feedback circuit that sensed arterial pressure (AP) and automatically computed the frequency (STM) of a pulse train required to stimulate sympathetic nerves via an epidural catheter placed at the level of the lower thoracic spinal cord. An operation rule was subsequently designed for the BBS using a feedback correction with proportional and integral gain factors. The transfer function from STM to AP was identified by a white noise system identification method in 12 sevoflurane-anesthetized patients undergoing orthopedic surgery involving the cervical vertebrae, and the feedback correction factors were determined with a numerical simulation to enable the BBS to quickly and stably attenuate an external disturbance on AP. The performance of the designed BBS was then examined in a model of orthostatic hypotension during knee joint surgery (n=21). Without the implementation of the BBS, a sudden deflation of a thigh tourniquet resulted in a 17+/-3 mm Hg decrease in AP within 10 seconds and a 25+/-2 mm Hg decrease in AP within 50 seconds. By contrast, during real-time execution of the BBS, the decrease in AP was 9+/-2 mm Hg at 10 seconds and 1+/-2 mm Hg at 50 seconds after the deflation. CONCLUSIONS: These results suggest the feasibility of a BBS approach for central baroreflex failure.

Aged↗
PubMed1988

Bionic larynx: electronic control of the reimplanted organ in the dog.

Complete rehabilitation of paralyzed head and neck structures has been difficult, and attempts at reinnervation of striated muscles have not consistently succeeded. Recent studies have shown that disabled muscles can be electronically "paced." This, together with recent developments in microelectronics, has led to the concept of the Bionic Larynx. The current experiments involve transposed nerve-muscle pedicles used to selectively reinnervate larynges which were denervated, entirely detached from the animal except for their vascular supply, and then reimplanted. These pedicles were later stimulated using a potentially implantable "pacing unit." It was possible to selectively control the critical functions of the larynx, using as stimuli physiological events that are preserved even when the vocal folds are paralyzed or uncoordinated. Although laryngeal transplantation in humans remains theoretical, these studies show that it could be feasible in the future.

Animals↗
PubMed2005

[Bionic surface design in metal on metal bearings for total hip arthroplasty--optimization of tribological characteristics].

Bionic systems are aiming to integrate natural observing into mechanical solutions. This has been realized in the design of metal on metal bearing in total hip resurface arthroplasty. The articular side of the femoral cup is covered with a dimple like surface. Under laboratory condition this so called "surf-metal-cup" achieved a reduction of the mechanical wear to almost a third part in comparison to a metal-cup with plane surface. This advantage, caused by the reduced friction-coefficient due to improved hydrodynamic lubrication could also be proved under laboratory conditions. The clinical introduction is expected to offer a significant extension of durability in this prosthetic system and needs to be proved in a long-term study.

Bionics↗
PubMed1985

The study of spectra and X-ray crystal structure of a novel bionics insecticide--(CH3)2NHCH(CH2S2O3)2Na X H2O.

IR and NMR spectra of novel bionics insecticide--C5NS4O6H12Na X H2O have been studied. The molecular and crystal structures of the compound also have been determined. The compound crystallizes in the monoclinic space group C5(2)h-P21/n with a = 8.0972(9)A, b = 16.262(4)A, c = 10.370(3)A, beta = 94.26(2)degrees and z = 4. The result shows that N atom in this compound captures a proton to form HN+ group, Na+ is in statistical disorder. Therefore, the structural formula of the compound is (CH3)2HN+-CH(CH2S2O3-)2 X 1/2(Na+)2 X H2O.

Bionics↗
PubMed2000

Informed parental consent for cochlear implantation of young deaf children: social and other considerations in the use of the 'bionic ear'.

This paper examines the social parameters surrounding the management of informed consent procedures for the parents of young deaf children for the surgical fitting of a cochlear implant ('bionic ear') to their child. Although most observers of this remarkable and well publicised medical development only see benefits in its use, the authors examine the nature of the conflict which has emerged between medical and media portrayals of the 'miracle' device and contrasting social, cultural and linguistic views of many Deaf people. The paper analyses the components of parental consent procedures for surgical implantation of their child, covering the risk-benefit analysis and, in particular, the information base that is provided for parents about the social construction of a 'Deaf life' by many Deaf people.

Child↗
PubMed2001

Bionic wavelet transform: a new time-frequency method based on an auditory model.

In this paper, a new adaptive wavelet transform, named bionic wavelet transform (BWT), is developed based on a model of the active auditory system. The most distinguishing characteristic of BWT is that its resolution in the time-frequency domain can be adaptively adjusted not only by the signal frequency but also by the signal instantaneous amplitude and its first-order differential. The automatically adjusted resolution, even in a fixed frequency along the time-axis, is achieved by introducing the active control of the auditory system into the wavelet transform (WT). Other properties of BWT include that: 1) BWT is a nonlinear transform that has high sensitivity and frequency selectivity; 2) BWT represents the signal with a concentrated energy distribution; and 3) the inverse BWT can reconstruct the original signal from its time-frequency representation. In order to compare these three properties between BWT and WT, experiments were conducted on both constructed signals and real speech signals. The results show that BWT performs better than WT in these three aspects, and that BWT is appropriate for speech signal processing, especially for cochlear implants.

Algorithms↗
PubMed2002

The application of bionic wavelet transform to speech signal processing in cochlear implants using neural network simulations.

Cochlear implants (CIs) restore partial hearing to people with severe to profound sensorineural deafness; but there is still a marked performance gap in speech recognition between those who have received cochlear implant and people with a normal hearing capability. One of the factors that may lead to this performance gap is the inadequate signal processing method used in CIs. This paper investigates the application of an improved signal-processing method called bionic wavelet transform (BWT). This method is based upon the auditory model and allows for signal processing. Comparing the neural network simulations on the same experimental materials processed by wavelet transform (WT) and BWT, the application of BWT to speech signal processing in CI has a number of advantages, including: improvement in recognition rates for both consonants and vowels, reduction of the number of required channels, reduction of the average stimulation duration for words, and high noise tolerance. Consonant recognition results in 15 normal hearing subjects show that the BWT produces significantly better performance than the WT (t = -4.36276, p = 0.00065). The BWT has great potential to reduce the performance gap between CI listeners and people with a normal hearing capability in the future.

Cochlear Implants↗
PubMed1999

[Comparison of constituents extracted from prepared Licorice by semi-bionic extraction with those by water extraction].

OBJECTIVE: To study the granulation of prepared licorice. METHOD: Semi-bionic extraction(SBE) and water extraction(WE) were used in the extraction of prepared licorice, and then compared with glycyrrhetinic acid, total flavone and extract with which were taken as the indexes. RESULT: SBE is superior to WE. CONCLUSION: It is better to use SBE in the preparation of oral licorice granules.

Drugs, Chinese Herbal↗
PubMed1999

[Comparison of semi-bionic extraction and water extraction in extraction of chemical constituents from processed cortex Phellodendri].

OBJECTIVE: To Study the granulation of processed Cortex Phellodendri. METHOD: Take berberine, total alkaloids and dry extract as indexes to compare the semi-bionic extraction (SBE) with water extraction (WE). RESULT: In 5 kinds of phellodendron bark solution, berberine, total alkaloids and dry extract obtained by SBE are much better than those obtained by WE. CONCLUSION: In the preparation of oral granules from processed Cortex Phellodendri, SBE is superior to WE, when the pH value is adjusted by HCl solution to 1.0 in the first decoction, adjusted by saturated Ca(OH)2 solution to 7.0 in the second decoction and to 10.0 in the third decoction respectively.

Alkaloids↗
PubMed2005

Healthons: errorless healthcare with bionic hugs and no need for quality control.

Errorless, invisible, continuous and infrastructure-free healthcare should become our goal. In order to achieve that goal, we need to rapidly move from current episodic and emergency-driven "healthcare delivery system" to an intelligent and extelligent health environment. That requires introduction of distributed affective Intelligent Caring Creatures (ICCs) consisting of healthons. Healthons are tools combining prevention with diagnosis and treatment based on continuous monitoring and analyzing of vital signs and biochemistry. Unlike humans, who posses only two or three dimensions of thinking, healthons can assure errorless health because of their adaptability, flexibility, and multidimensional reasoning capability. ICCs can do "the right thing" based on (1) state-of-art medical knowledge, (2) data about emotional, physiological, and genetic state of a consumer and (3) moral values of a consumer. The transition to the intelligent health environment based on ICCs requires the solutions to many currently unsolved healthcare problems. This paper lists the unsolved problems (by analogy to mathematical unsolved problems list) and explains why errorless healthcare with bionic hugs and no need for quality control is possible.

Artificial Intelligence↗
PubMed1991

Bionic organs.

When a lizard loses its tail, a new caudal appendage soon grows to replace the one that is missing. But when a human loses a kidney, severs a peripheral nerve or worse, the spinal cord, that organ is lost forever. Such at least is conventional thinking. But imagine that the victim of an industrial accident with a paralyzed hand could achieve new levels of function by inducing axonal regrowth through a synthetic nerve guidance channel; or that a Parkinsonian patient's symptoms could be relieved by implanting in his brain neural tissue encased in a selectively permeable polymer envelope; or that the inexorable progression of the vascular complications of juvenile diabetes could be stopped, even reversed, by a membrane-protected xenograft of insulin-producing tissue. This is the dream of bionic organ science. It is predicated on two lines of technological achievement: the availability of ultra-thin, biocompatible, selectively permeable polymer membranes which can protect a transplant against immune rejection while allowing solute exchange between the graft and its environment; and the synthesis of novel materials, some biostable, some bioresorbable, which can serve as scaffolding or anchor for tissue regrowth in the geometrically and chemically controlled environment of an implant. The fabrication, growth and survival of composites of living tissues with synthetic polymers, often enhanced by the incorporation of specific cell growth factors or inhibitors, has been demonstrated at the tissue culture level, and extended in vivo to experimental models of human endocrine deficiency or neurological defects. The key to progress with bioartificial organs is the confluence of knowledge ranging from materials science to cell and molecular biology to experimental surgery. Obstacles to clinical implementation of this new therapeutic concept include: large scale procurement of specific tissue structures or isolated postmitotic cells from animal sources; demonstration of safety and efficacy of spontaneously occurring, bioactive tumor cell lines; verification of long-term stability and bio-acceptance of polymer implants; and industrialization of the fabrication process to meet quality control, shelf-life and commercial distribution requirements.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMedDate not supplied

[Design aspects and hydrodynamic characteristics of the Bionics heart valves].

It has been shown that Bionics prostheses compare very favorably with bioprostheses based on rigid supporting frameworks. The advantages of the above prostheses lie in the fact that the supporting frameworks of changed stiffness used in their modelling possess damping capacities at minute physical loadings, which considerably improves the hydrodynamic characteristics of biovalves.

Animals↗
PubMed1995

[Exploration on oral preparations of Chinese materia medica by semi-bionic extraction].

In the light of biopharmacy, the present new technology to extract oral preparations of Chinese traditional medicinal by semi-bionic method was designed. In the technological process, the prescribed drugs were decoction and extracted first in an acid solution with a certain value and then in an alkaline solution with ther pH value. Afterwards, the extracts were filtered concentrated, dried and made into preparation. The theoretical basis of this technology was analysed and the concrete procedures were introduced, with Shaaogan Zhitong pill as an example.

Drugs, Chinese Herbal↗
PubMedDate not supplied

Bionics, biological systems and the principle of optimal design.

The living world is an exciting and inexhaustible source of high performance solutions to the multitude of biological problems, which were attained as a result of a natural selection, during the millions and millions years evolution of life on Earth. This work presents and comments some examples of high performances of living beings, in the light of the universal principle governing the realm of living matter: Optimal Design Principle. At the same time, the transfer of these optimal solutions, from living matter to the technologies, is also discussed. This transfer is offering new and fertile perspectives to future technologies, which must be more efficient, cheaper and in perfect harmony with the biosphere.

Animals↗