>>1
§ Reflective Displays
Liquid crystals on silicon have been developed as optical engines for projection and virtual display systems.
This LCOS ( liquid crystal on silicon ) is called microdisplay, it’s regarded as a reflective image transducer too.
Besides, it’s capable of accepting video signals & converting signals into a high bright, high contrast, large-sized image.
a CMOS transistor and a capacitor are fabricated and connected in the silicon backplane.
The CMOS transistor could support high data rate due to the high electron mobility of single-crystal silicon.
The electron mobility of c-Si is about two orders higher than that of amorphous silicon in magnitude.
>>2
The reflective aluminum electrode is connected to drain of the transistor and capacitor through a light-blocking metal layer.
The aluminum pixel mirror gets near reflectivity of 91 % after smoothing.
The dimension of the electrode is 13 × 13 μ and the gap between electrodes is 0.5 μm. Thus, the aperture ratio is about 93 % .
For a 1365 ( H ) × 1024 ( V ) imager in a 4 : 3 aspect ratio, imager in a 4 : 3 aspect ratio, the diagonal is 23 mm.
>>3
Two types of projection displays with LCOS ( Liquid Crystal on Silicon ) have been actively developed such as rear projection TVs and near-eye projection.
Three LCOS panels with 1280 × 720 resolution elements are used in a recent fruit ( about 2003 ). The display slightly has the thickness of 20 inches due to the adopted reflective optics.
>>4
Optics to create virtual magnified images is used in a display called ‘Virtual Projection’ . An user feels to be into a small viewfinder.
As we are concerned with reducing weight & cost, a single high-resolution and high speed LCOS is commonly used as optical engine.
Three sequential color LEDs are used to show full-colored images. And those LEDs have fast response time, light weight, high brightness, low power consumption and long lifetime. Thus, they are regarded as ideal light sources for virtual projection displays.
>>5
As light weight and high-magnification projection are main merits for virtual display, if a 12.7 mm diagonal LCOS imager ( 800 × 600 pixels ) is used as an object, the required magnification reaches about 15x to view an equivalent 19’’ display at about 2 meters away. Simple optics such as a magnifying glass or an eyepiece are often limited to a maximum magnification of about 10x .
>>6
Compound optical systems such as microscopes enable much higher magnification, but they are bulky to be wearable.
A folded compound magnifier has been developed to achieve a large magnification.
The eye-relief is about 20 mm and exit pupil is 10 mm.
一
>>7
In addition, LC response time can be regarded as a major challenge for color sequential virtual display.
For a frame rate of 85 Hz, the LC frame ( rise ＋ decay ) time needs to be shorter than 3.9 ms to avoid color breakup.
LC cell gap as thin as 1 μm has been considered and color sequential operation from −10 ℃ to 70 ℃ has been demonstrated to realize such a fast response.
Though thin cell is favorable for improving LC response, it’s more difficult to manufacture such the cell.
At that time ( 2003 〜 2004 ), as I worked in a certain company located in Fukaya-city of Saitama-prefecture in Japan ( ※ ), I also had heard of the methodology.
※ TMD ;
a company which was founded on a joint investment of T and P
Strangely, though there are many research fruits about influences of light through liquid crystalline molecules on sub-consciousness, those results have been scarcely known.
>>8
§ New Liquid Crystal Display Principles
・ Ferroelectric Liquid Crystals
In general, ferro-electric liquid crystals utilized in technological fields are not categorized into nematic LC, SmC’ type is exceptional.
It can be solved that such a phase always has a spontaneous electric polarization of the smectic layers by taking symmetry into consideration.
Because the dipole moment is connected to the molecular orientation and it points into the same direction for every molecule in the ordered layers of a SmC’ phase.
>>11
If all layers would have the same preferred orientation of the molecules ( directors ), this would add up to a macroscopic polarization like that of an electrete. Of course, such a structure has a high self-energy.
But, in the smectic liquid crystal, the orienting forces between different layers gets small, therefore, this situation can be avoided by rotating the director around the layer normal from one layer to the next.
In this structure, the polarization of each layer is also changing from layer to layer, and the total polarization is kept 0 .
一
>>12
If such a liquid crystal is put into a cell which is thinner than a helical pitch (〜 2 μm), the helix structure is lost.
Because a tendency to arrange parallel to a surface becomes stronger than electric forces.
Then, there are only two energetically equivalent ways to orient the molecules.
>>13
The polarization which is now always vertical to the cell walls can either point ‘upwards’ or ‘downwards’ . One can switch between two energy minima by applying an external field.
The polarization then follows the typical hysteresis behavior of ferroelectric or magnetic materials.
Because this type of structure only occurs between close walls, the correct name is ‘surface stabilized ferroelectric liquid crystal ( SSFLC )’ .
>>14
For a display devised on SSFLC , there will be only an ordinary beam which keeps its linear polarization. The polarizer on the exit side is vertical to the other and therefore blocks the light almost completely.
一
>>15
If the cell is switched to the other state, parallel relations between those molecules and incoming polarizations are lost.
Therefore, an extraordinary beam is in addition generated with different wavelength and phase difference. The light varies from linear state to elliptical polarization. The parallel component is transmitted through the analyzer on leaving the cell.
Because the polarization isn’t completely twisted as in a TN cell, but the transmission is only partially changed. Accordingly, such an open state is called ‘grey one’ here.
>>16
The main merit of SSFLC is its fast switching behavior. Those dipole moment switching times of 10 μs can be realized because of the direct field coupling with molecules.
This is more than 1000 times faster than the switching time for nematic devices, Therefore, this type of cell is suitable for video application, we must take the importance to reproduce fast changing patterns into consideration.
>>17
In this case, problems of loss of orientation between row addressing strobes are not found out in nematic displays.
Even if an external field is switched off, its state is kept stably by those cells due to bi-stable ferro-electric characters.
一
>>18
An important quality improvement has been obtained by remarkably increasing viewing angle.
Because the molecules are not slanted to a cellular plane, there is substantially no difference in bi-refringence property for an oblique beam.
一
>>19
An other merit is downsizing of pixel because of use thin cells. We have realized a nematic display of about 5 μm SSFLC pixels ( in 2003 ).
Though this condition is much better than the requirement at present for PC display ( ※ ), it makes this display useful for micro-display such as light-valves for projectors or head-mounted displays.
※ For example, each pixel of 14’’ in diagonal is adopted in an XGA 768 × 1024 display, and, the subpixel of the representative single-coloured display is 90 μm in wideness.
>>20
But, demerits in performance can be induced by smallsizing.
1 ) In principle, grey scales can’t be induced because of bi-stability. But, techniques to produce grey levels have been already realized for nematic cells in digital fields, such as frame rate modulation & spatial dithering. Especially, the latter technique is easier to use here because of small pixel size.
2 ) In case of thin cells, complete changes in polarization direction are not brought as in TN cells. Accordingly, the transmitting state isn’t completely at ‘white’ condition. This necessarily causes a strong backlight.
>>20
But, demerits in performance can be induced by smallsizing.
1 ) In principle, grey scales can’t be induced because of bi-stability. But, techniques to produce grey levels have been already realized for nematic cells in digital fields, such as frame rate modulation & spatial dithering. Especially, the latter technique is easier to use here because of small pixel size.
2 ) In case of thin cells, complete changes in polarization direction are not brought as in TN cells. Accordingly, the transmitting state isn’t completely at ‘white’ condition. This necessarily causes a strong backlight.
>>21
On the other hand, it’s more complicated to produce ferroelectric cells.
While a twisted nematic structure spontaneously appears between orienting surfaces, a SSFLC structure must be generated by a definite phase sequence.
Isotropic liquid crystals filled in a cell are first cooled down into nematic phase, those liquid crystals are oriented parallel to the brushing direction of cellular walls.
Liquid crystals are put into the SmA phase with parallel molecules and vertical layers to the brushing direction respectively on further cooling.
>>24
Molecules arranged in the same layer are left due to further cooling, but those orientations also are changed to oblique objects of the SmC’ phases.
This phase sequence ( isotropic → N → SmA → SmC’ ) is indispensable for obtaining correct macrostructures, but it’s not ensured by every type of liquid crystal.
Because small irregularities during cooling process can cause wrong orientated domains and they may unstabilize a display.
>>25
But the main demerit of ferroelectric liquid crystal display is that the structure may be lost by mechanical stress during use of display.
If an ordinary nematic display is gently pressed, its functions will be lost for a short moment. Because the twisted structures are distorted. This may lead to non-desired colors of even a complete ‘blackout’ .
But after the secondary fraction, the structure will be recovered and the display will work normally again.
>>26
Unfortunately, this is not true for a ferroelectric display. As soon as domains losing right orientation are re-built, they will remain stable.
In this case, it can be seemingly interpreted that small cracks have obstructed commercial use of this type of display over a large scale for now ( about 2003 ).
This kind of small-sized display is important only for specialized applications, it’s not possible for the users to touch the display ( such as head-mounted displays, projection displays ), such displays are not commercially available.
>>28
§ Polymer Dispersed Liquid Crystals
Here, a rather different technology from the preceding is introduced. The devices considered here work at ‘scattering mode’ . The displays presented before all work through a liquid crystal cell to change the polarization. And, this change of polarization is converted into controllable absorption with a secondary polarizer.
The displays ideally switch between transparent state and black state. In contrast, displays at scattering mode switch between a transparent state and a milky white state, light is diffused under the condition. Interestingly, the first experimental display was categorized into this type. But, the display was not commercially successful.
>>30
An intrinsically homogeneous liquid crystal is used by these first displays ( turbulences are caused by electric field ), meanwhile, polymer dispersed liquid crystals are inhomogeneous.
Small liquid crystalline droplets of 〜2 μm are embedded in a solid polymer matrix.
In the case, a liquid crystal is chosen so as to satisfy the following condition. Namely, the ordinary index of refraction o’ is identical to the isotropic index of refraction of the polymer.
If no fields are applied to those directors, those droplets in the liquid crystal have random orientation.
>>31
Therefore, the refraction index bearing orientation-dependent mixture of ordinary indices & extraordinary indices will be different from that of polymer. Consequently, a light beam will be scattered by those droplets.
If a field is applied to liquid crystals parallel to lights, the directors will be oriented with response to the applications of fields. Then, the ordinary refraction index for liquid crystal will express strong influence.
This means that a difference in index disappears, and it enables scattering.
一
>>32
Monomer can be mixed with liquid crystal before polymerization. In starting polymerization, growth chains are preferred to each condition of two phases due to entropic reasons. Therefore, a spontaneous demixing can take place, it causes the segregation of liquid crystal into small droplets.
The same phenomenon can be caused after polymerization by cooling polymer melt / liquid crystal mixture if the phase diagram contains an upper consolute temperature.
一
>>33
If polymer and liquid crystal are immiscible but both matters are soluble in a common solvent, such a solution can be dried.
When the solved content is lowered, phase-separation will occur.
Finally, micro-encapsulation techniques known in pharmacology can be applied to first create encapsulated liquid crystal materials which will be mixed with a melting polymer.
All of these methods are comparatively inexpensive. Therefore, it’s possible to produce polymer dispersed liquid crystals in large quantities such as foil materials of square-meter size.
>>34
Because the application is at low price, it’s possible to produce ‘switchable windows’ .
Besides, those windows can be switched electrically from a transparent state to an opaque state. So, he application of it to display devices is under consideration ( about 2003 ). Especially, we are concerned with whether a beam is absorbed in it or scattered out of its path for projection devices. The latter may be even more desirable, because the energy is not deposited within the cell.
>>35
However, if a field is applied to the liquid crystals, the incomplete orientation is caused. It prevents a more widespread use of scattering mode devices.
Liquid crystal molecules close to surfaces of drops tend to be oriented parallel to a surface rather than a field.
一
>>36
This causes a remaining scattering viewed as smokiness on a window and low transmissions for projection devices.
Furthermore, in general, the applied voltages get higher than those for super-twisted nematic type displays.
一
I have remembered that a foreign engineer visited the company to produce displays ( >>9 ) on one day in 2004 , he pointed out the ‘smokiness’ as a noticeable point.
>>38
§ Summary
Liquid crystals have been known and studied since the 19 th century. Nevertheless, they didn’t gain their enormous technological importance until about 30 years ago. Main characters of liquid crystal molecules enabled themselves to use as displays such as optical anisotropy and dipole moment.
The anisotropy of them allows to control transmitted lights due to bi-refrigence. Meanwhile, the dipole moment of molecules allows to control their orientation by an electric field.
>>39
The first successful ‘light valve’ cells was constructed on these principles with a twisted nematic plane.
In this structure, the nematic order is artificially distorted to be a helical one. In case of the structure, it’s possible to rotate the plane of polarization by a controllable amount through an electric field.
>>40
As the demands on displays ( such as resolution, gray scales, colors, etc ) grew mainly because of applications in information technology, the limits of simple TN cells became obvious.
Though elaborate multiplex addressing schemes were developed, it could be proven that there are mathematical limits on them for the number of pixels composing a display.
一
>>41
Therefore, the basic principle of TN cells was improved along two different pathways ;
( 1 ) The twist angle was raised to obtain rather weak stability, such a rather weak stable structure is easy to be controlled electrically. And, a small difference between ‘on’ and ‘off’ in voltage alternately enables addressing of larger arrays of pixel. In most cases, this rather less expensive solution is used in middle quality display such as those for mobile phones ( in 2003 ).
>>42
( 2 ) A transitive method from ‘passive’ displays to ‘active’ matrix is performed onto cell walls by integrating the final stage of the addressing electronics, such as TFT ( thin-film transistor ).
It’s theoretically unlimited to raise size & resolution through this approach and it has been realized to maximize high-end applications for computer monitors.
>>43
Besides, these technical, quantitative improvements on fundamentally different principles also have been explored. For example, we could solve several demerits of traditional TN type cells with ferroelectric liquid crystal structures.
It’s possible to control them faster, furthermore, they can have a larger viewing angle and smaller pixel size.
And, it also is possible to construct large area devices at low cost with polymer dispersed liquid crystals. Nevertheless, we have never achieved an important market share with these radically different technologies until now ( in 2003 ).
>>44
Severe competitions were developed over mass-production of excellent displays.
We suppose that great pressures were applied to researchers engaging in those projects.
In fact, two developers who had worked in the company ( >>9>>38 ) committed suicide at that time ( about the beginning of the 2000 s ).
§ Performance Estimation for the Human Brain
The human brain is an organ whose weight is about 1.4 kg and it can be subdivided into following three parts.
・ Forebrain ( cortex, basal ganglia, hippocampus, fhalamus ) consists of two hemi-spheres ( left & right ). The part is about 80 % of the whole brain in weight.
・ Mid-brain
・ ( Be- ) hind-brain ( pons, cerebellum, medulla )
In the following, we will list few facts which may have relation to information processing in brain.
>>50
The cortex consists of an inner part, the white matter and a highly convoluted outer part of grey matter.
This grey matter is made of a high density of non-myelinated neurons ( inter-neurons and others ), meanwhile the white matter mainly consists of myelinated axons of projection neurons inter-connecting the left hemisphere & the right one and other parts.
к
>>51
The major bridge between two hemispheres is called corpus callosum, the organ contains 2 × 10＾8 axons. Those axons pass through a cross section of about 6 cm＾2 in the center.
Besides, each axon cross section of 3 μm＾2 can be found out in each part.
>>52
The total surface area of a cerebral cortex is about 1800 ± 200 cm＾2 , the organ has an about 2 〜 3 mm layer in thickness.
It’s estimated that about 10＾11 neurons are usually contained in a brain, and about 2 × 10＾10 neurons are located in a cerebral cortex.
>>53
We calculate a neuronal density of 4 × 10＾7 neurons/cm＾3 from this data. This corresponds to an average volume of 2.5 × 10＾4 μm＾3 per neuron, and an average linear distance of about 30 μm between neurons.
Every neuron has some thousands 〜 a few ten thousands synapses.
>>54
If we assume an average value of 10＾4 synapses per neuron, we obtain an average volume of 2.5 μm＾3 per synapse.
Each neuron is connected to every other neuron in a vortex through below four neurons in average due to the high number of synapses per neuron and the distribution of connections.
The mechanism essentially realizes the transistor functions in an area compared with CMOS technology, the cortex arrives at its enormous numbers of functional units at a relatively large distance between units because of 3-dimensional packing in cortical layer.
>>55
According to the state of an organism ( sleep, awakeness, awareness, action ), a region in a cortex,
a firing rate of action potential spikes is within a range from below 10 s＾−1 to more than 100 s＾−1 .
One needs to multiply these rates by about 2 × 10＾10 × 10＾4 ＝ 2 × 10＾14 synapses and the number of bits transferred per spike to obtain numbers of information processing capabilities of a cortex.
>>56
The formal result of calculation must be corrected due to redundancies in the processes and for ways called control & glue logic within the cortical neural network.
They could be easily reduced by some orders of magnitude. But, the actual value has never been known yet ( about 2003 ).
с
>>57
Meanwhile, correlation effects can lead to an increase of processing efficiency.
In any case, these numbers have to be regarded as upper limits for the formal processing rate.
But, that does not hold at all accounting, for the semantics of the processed information and its redundancy.
а
>>58
It’s not meaningful to directly compare processing capabilities of a cortical neural network with those of a supercomputer so much.
Because both mechanisms are mutually very different in architecture.
We summarize some features of this difference and its implication.
>>59
Supercomputers are based on a very coarse-grained parallel architecture with high-speed CMOS processors, and the computation function is separated from the memory function in the grains under traditional mechanism.
They are optimized so as to reach extremely high FLOPS values, and they are desirable for simulation tasks.
т
>>60
In contrast, a very fine-grained neural network architecture of a cortex is built from stochastic elements, the computation function and the memory function are integrated at micro-scale under the mechanism, it exhibits a constant re-programming of the entire system, and it has many characters of analog computation with a menu of linear & non-linear operations.
Besides, cortical neural networks are optimized by this system for fast recognition, interpretation of complex pattern, non-linear association and all aspects related to consciousness.
с
>>61
Meanwhile, the formally huge processing capability and memory can’t be accessed at random.
And, according to detailed studies, it’s known that only a tiny fraction of information can be reliably transferred from ultra-short and short term memories to long term memory.
>>62
The latter can’t be filled at rates larger than 0.2 bit/s 〜 2 bits/s independently of type of information ( such as textures, sounds and images ).
This means that even if we constantly learned at highest rate during awaken periods, we can’t store more than about 20 〜 200 MB of information in long term memory during a mean lifespan of about 75 years.
7.2.7 Bio-films and technologies to suppress the development of infectious disease and to prevent infection
Patients suffering from intractable diseases such as fracture, infectious disease and periodontosis are rapidly increasing with the appearance of aging society.
To aim at improvement in QOL ( Quality Of Life ) for aged people, prolongation of healthy lifespan,
improvements in dietary life and lifestyle to keep the balance between immune mechanism and autonomic nervous system, fulfillments of composite-cooperative medical treatment and alternative medical treatment are being regarded as most important tasks from the viewpoint of preventive medicine.
а
>>64
In particular, it’s predicted that the rate of vulnerable patients to infection to aged people and patients with weakened immune function rises.
Accordingly, it’s urgent to prepare preventive measures against intractable diseases such as infectious disease with bio-film.
>>65
We explain about kinds, characters, formations and influences on a living body of bio-film and show clinical instances of intractable diseases.
Besides, we propose ways to gradually stream a proper quantity of antibiotics out of a solid tablet to reform the surface of bio-material here.
с
>>66
7.2.7-1
Concepts of bio-film and its characters
A viscous matter called bio-film is composed of diverse microbes ( such as bacteria, fungi, algae, protozoa ), extracellular polymers, inter-stitial waters.
This cellular cohesive lump of microbes strongly sticks to the surface of a solid.
к
>>67
Complexes (≒ communities) of different bacteria in kind are formed at finite nutrient, symbiotic environment in a biofilm.
Proteins are synthesized by plural bacterial aggregations, they generate genes and features of biofilm sequentially varies.
Furthermore, as bacteria in a biofilm are enclosed with extra-cellular matrices, they have resistance to immune cells and anti-bacterial matters.
>>68
7.2.7-2
Formations of biofilms and periodontosis
Biofilms are formed through adhesions of microbes and matter-transfers in an interface between solid phase and liquid phase.
Bacteria floating in a liquid stick to the surface of a solid, micro-colonies are formed with matters secreted by those bacteria, after that, a symbiotic state of several kinds of bacteria appears.
一
>>69
And, those micro-colonies turn out to be a biofilm.
Channels to let waters pass are formed in the biofilm,
exchanges of nutrients, removal of waste products, transfer of a small quantity of oxygens, etc are efficiently performed between different bacteria in kind through those channels.
Furthermore, different bacteria in kind are issued from a mature biofilm to a liquid, a new biofilm is synthesized through the same process as the above.
а
>>70
Biofilms in medical field are mainly classified into ① biofilms formed on living tissues and ② those formed on medical biomaterials.
In particular, biofilms belonging to ① cause tooth decay, periodontosis, inflammation of the middle ear, bacterial prostatitis, cystic fibroid pneumonia, etc.
>>71
Meanwhile, biofilms categorized into ② cause infections through suture, contact lenses, artificial heart valve, artificial urethra and cystitis through urethral catheter, etc.
About 700 kinds of bacteria are living in an oral cavity, for instance, dental plaque is a typical biofilm sticking to the surface of tooth in an oral cavity.
>>72
This dental plaque is composed of 400 kinds of bacteria.
But, bacteria living on the surface of tooth in an oral cavity are different from those in a periodontal pocket in kind.
And, oral biofilms are easily formed on brackets and wires habitually utilized for dental remedial treatment.
Different bacteria in kind grow with exchanging matters and informations mutually, the composition and the function of the biofilm are determined at respective conditions dependently on interactions with its environment and quorum sensing.
к
>>73
Pathogenic biofilms cause tooth decay, periodontosis and diseases around implants, etc.
Bacteria and products released from biofilms are spread through a circulatory system, conflicts between them and bio-defense mechanisms cause inflammations and consequently, they injure periodontal tissues.
н
>>74
7.2.7-3 Spinal infectious disease and technologies for removal of biofilm
According to investigations by Japanese society for study of bone and joint infections,
respective infectious rates after orthopedic surgery in 2004 were as follows.
・ Replacement with an artificial knee joint ; 1.5 %
・ Replacement with an artificial hip joint ; 0.7 %
・ Spinal instrumentation ; 3.7 %
In case of infectious to locomotive organs,
not only blood level of anti-bacterial medicines but also influences of anti-bacterial medicines on respective tissues ( such as bone, cartilage, soft tissues, inter-stitial fluid, tumor, necrotic tissue, parts around an implanted biomaterial, etc ) are important. Namely, we must take bacterial sensitivities and transient influences on respective tissues into consideration to effectively use anti-bacterial medicines.
>>75
Especially, bearing infections through an implanted material in mind, as a biofilm formed by bacteria enables the cancellation of anti-bacterial medicine and promotes the durability against the medicine,
it’s necessary to break down the biofilm and suppress its formation.
>>76
One case of spinal infection is shown in the following.
The lateral NMR-image and the lateral X-ray image of the lumbar vertebra of a patient suffering from fungal infections are shown in a Fig .
This is a case of a 72-years old man.
After an abdominal operation for acute pancreatitis, this case of spinal infection was originated in infections around the operated part.
т
>>77
Those T1 weighted images show a wide infection spanning from the third lumbar vertebra to the fourth lumbar vertebra.
Though an antibiotic had been given to the patient by the former doctor, the infection was not weakened.
So, after two months from the start of the treatment, the patient was transferred to the hospital belonging to Hokkaido university.
The patient had a severe lower back pain, its inflammation got harder.
р
>>78
And, the medical team failed to determine bacteria causing the inflammation through blood culturing.
Besides, as the whole body of the patient was at bad condition, the medical team avoided a high invasive operation such as spinal reconstruction, they adopted a minimum invasive operation.
As it also was probable that those inflammations were caused by suppurative bacteria,
they avoided the surgeries with inner-vertebral fixative metals and washed the infectious focus with a curette through a rear lateral vertebral endoscope to grasp bacteria causing inflammations and suppress infections.
а
>>79
Namely, a minimum invasive curettage washing was performed on this symptom at awakening condition with topical anesthesia and venous anesthesia.
The Ministry of Health, Labour and Welfare of Japan permitted the hospital belonging to Hokkaido university to perform the operation as an advanced medical treatment in June. 2011 .
с
>>80
The operation took 48 minutes to finish.
Candida as a kind of fungus was extracted from the infectious focus picked out through this operation.
After this treatment, an anti-fungous medicine was given to the patient for 14 weeks, so that, the spinal infection was completely cured.
一
>>81
According to a X-ray lateral image after two years from the treatment, we find out that newly generated bones have been formed around infectious parts at that time ( the whole vertebral body ) and the infection has been cured.
By the way, in this case, as local deformed kyphoses of the third and the fourth lumbar vertebra have got more manifest, it’s urgent to cure such a symptom without leaving deformation for now.
>>82
Infections of fungi on vertebrae are very rare, in many cases, even though an antibiotic is given to such an infectious case for a long term, the state of the whole body gets be at bad condition.
Therefore, it’s very difficult to cure most of the such the cases due to fall in immune function.
And, in Japan, spinal re-constructive methods with biomaterials such as specific metals have not been applied to infections of suppurative bacteria and fungi on vertebrae so much ( in 2013 ).
Because such ways tend to cause delays of infection and its recurrence.
>>83
Meanwhile, in case of infection by tuberculosis germs, as only small quantity of biofilms is formed, it’s supposed that it has no difficulty to use a metallic biomaterial for medical treatment.
As the above case, it’s possible to clean up an infectious nest with a curette by a minimum invasive operation with an endoscope, besides, such an operation enables us to promote blood-stream and improve penetration of antibiotic.
>>84
7.2.7-4
Reformations of the surface of bio-ceramics and measures against infectious diseases
To cure intractable infectious diseases, it’s strongly desired to utilize ‘sustainingly released proper quantities of anti-bacterial medicines, chemicals to in-activated osteoclasts and bone-morphogenetic factors’ with biomaterials dependently on individual conditions of the whole body and implanted parts.
>>85
According to guidelines for prevention of surgical site infection issued from The Center for Disease Control & Prevention, it’s recommended to preventively apply anti-bacterial medicines to infections.
However, recently, the appearance of antibiotic-resistant bacteria originated in over-applications of antibiotic also has been reported ( about 2013 ).
>>86
Then, kinds and given quantities of used antibiotic are determined dependently on kind of applied bacteria to control increase of microbes and bacteria and cure infectious diseases.
In general, cefazolin as a cephem antibacterial medicine is effective against bacteria causing inflammations, it’s utilized as an antibiotic with finite effective range in medical fields.
>>87
Cefazolin has wide antibacterial spectra for gram positive ( or negative ) bacteria, it’s sold on the market as a kind of cefamezin for injection.
This is controlled so as to satisfy the blood level 0.13 mg・cm＾−3 for cellular inhibitory concentration 0.03 mg・cm＾−3 just after supplying.
>>88
Then, surface-modified granules of hydroxyapatite （ Ca 10 (Po4) 6 (OH) 2 , HAp ）in heterogeneous transfusions were produced by ultra-sonic processing to develop a bio-ceramics effective against infection and in bone-regeneration.
And, we investigated relations of characters to adsorb antibiotics and gradually release them with micro-structures ( of those products ) to grasp its surface characters.
>>89
Sprayed-dried HAp-granules ( produced by HOYA.corp , 20 〜 50 μm in diameter ) were immersed in respective transfusions.
※ Amino-U ( amino acid ), Amino-D ( saccharide, electrolyte ), Amino-C ( the mixture of Amino-U and Amino-D )
These amino fluids were produced by Otsuka Pharmaceutical Factory.Inc .
And, these were processed at 120 W, 38 kHz, dried condition by ultrasonic treatment, centrifugation, so that granular materials ( Amino-U/HAp, Amino-D/HAp, Amino-C/HAp ) were drawn.
※ Spherical HAp-granules could be derived from every transfusion through ultrasonic treatment for about 15 minutes.
>>90
In case of Amino-C/HAp-granules,
cohesive materials originated in transfusions stick to surfaces.
According to the pore size distribution curve, we can find out two peaks of mean sub-pore volume.
※ One is 3 〜 5 nm in diameter, another is 30 〜 60 nm in diameter.
>>91
Besides, striped cohesions of 10 〜 20 μm in size are found out in Amino-U/HAp-granules, elliptic cohesions of 1 〜 10 μm in size are found out in Amino-D/HAp-granules respectively.
These granules are roughly equal in specific surface area, the total pore volume.
These granules were added to a cefamezin physiological saline solution,
※ This saline solution was produced by Astellas Pharma.Inc .
it was agitated at 309.5 K and was processed through centrifugation.
>>92
And, the CFZ ( cefamezin ) equilibrium concentration and the adsorptive quantity of each processed result were measured by ultraviolet-visible spectroscopic analysis.
So that, a HAp-single-phase was formed around the adsorption.
As CFZ-adsorptive quantities of Amino-U, D, C / HAp got higher than that of HAp, this result indicated effectiveness of ultrasonic processing in transfusion.
к
>>94
Furthermore, granules dried at room temperature and frozen-dried granules were immersed in SBF at 309.5 K , pH 7.4 ,
they were agitated.
After that, successive variations of rates of CFZs controlled-released from granules were measured.
As the result, the controlled-release rate of frozen-dried granules was higher than that of granules dried at room temperature.
е
>>95
The controlled-release rates were listed up in order of Amino-D/HAp , Amino-C/HAp , Amino-U/HAp .
We could find out that the adsorption of CFZ through an amino acidic surface was especially strong.
Accordingly, it’s possible to properly design functions to sustainedly release CFZs as well as control detailed structures of HAp-granules by ultrasonic surface reforming at proper composition of transfusion and drying condition.
>>96
・ Conclusion
In preparation for advanced aging society, measures against infections through biofilms, overcoming those problems, controls and developments of micro-orgasmic interfacial engineering can unexpectedly or dramatically bring chances, challenges and changes to the extension of human lifespan.
Antibacterial activations of ceramics depend on respective conditions such as crystality, particle-size, specific surface area, structure of each pore and generated chemical kind, etc.
>>97
Besides, we should pay attention to not only anti-bacterial activations of TiO2 or Ag-carrying ceramics but also effectiveness of Zn-modified Ti-implant which is characterized by anti-bacterial features and osteo-adhesiveness of Zn-ion.
с
>>98
Technologies to prevent formations of biofilms under development are as follows ( about 2013 ).
・ Surface-reformations of antibacterial TiO2 and Catechin-sustained releasing antibacterial stent by laser-irradiation.
・ Effective sterilization of foodstuffs through electrolytic water and ozonic water
・ Washing out biofilms by plasma
・ Systems to remove biofilms with breakdown enzymes , etc.
It’s told that these images are descriptive features of New York which were genetically modified by Giger.
Namely, these sur-realistic urban spaces mean that they are categorized into exotic R＾4 s such as capped-gropes with organic characters.
9.2 Efforts of the ministry of economy, trade and industry for standardization
9.2.2 Materials used for an artificial joint
As dynamical safeties including durability give remarkable influences on a clinical result over a long period, excellent metallic materials in balance between strength and ductility are favorable in orthopedic fields.
Especially, if a component is implanted into a living body, the component must satisfy biological safeties and dynamical structural safeties.
It’s requested to evaluate its biological safeties under Good Laboratory Practice ( GLP ).
Meanwhile, its dynamical safeties must be evaluated at material level and product level.
>>104
Then, respective factors such as micro structure, strength, ductility, fatigue strength and corrosion resistance, etc are evaluated at material level.
Meanwhile, its safety and its effectiveness must be demonstrated according to uses for the product to evaluate performances of a product and qualities of the product.
Tests required for mechanical compatibility evaluation are far more than tests required for biological safety evaluation.
Because steps to produce materials composing the product must be checked to demonstrate performances of the product.
к
>>105
9.2-3 Factors to control biological safeties of a metallic material and ways to test those factors
In case of implant in a living body, biological safeties such as cytotoxicity, sensitization, genetic toxicity and properties related to implantation, etc depend on a quantity of metallic ions released from a material (≒ extent of corrosion resistance) owing to chloride ions contained in the marerial.
>>106
A quantity of eluted metallic ions depends on the strength of passive film ( oxide film ) formed on a surface of metal.
Then, a quantity of eluted metallic ions can be measured through an elution test, it’s possible to easily measure the strength of oxide film through an alternating impedance method and an anodic polarization test.
The denser and stronger an oxide film ( several nanometers in thickness ) formed in a surface of material is,
the harder to be melted the film gets.
>>107
Besides, a quantity of metallic ions eluted through the film also reduces.
So that, its biological compatibility is improved.
It’s possible to directly observe such an oxide film through a field emission transmission electron microscope ( FE-TEM ) after preparation by focused ion-beam ( FIB ).
Angle-resolved X-ray photo-electron spectroscopy ( AR-XPS ) is convenient to measure the state of an oxide film such as composition because it’s simple in measurement and Ar ( argon )-sputtering does not give influence on the measurement so much.
And, it’s possible to evaluate the stability of an oxide film through anodic polarization tests.
>>108
Furthermore, current densities at 0 mV and electric potentials at 10 μA/cm＾2 can be respectively drawn through anodic polarization tests.
It’s possible to compare the state of a material with that of an other material by checking drawn quantities.
The strength of an oxide film can be evaluated as a resistance value by an alternating impedance test.
>>109
And, an oxide film formed in a living body is abstracted with an equivalent circuit, the following formula holds in the equivalent circuit.
（ x − 2 R1+R2 / 2 ）＾2 ＋ y＾2 ＝ （ R2 / 2 ）＾2
Then,
x ; the real part of an impedance
y ; the imaginary part of it
The center is put at 〈（ R1+R2 / 2 ）, 0 〉.
And, it’s possible to determine a solution resistance R1 and a film resistance R2 by fitting actually measured data to theoretical data under a semi-circle having a radius of R2 / 2 from the center.
And, it also is possible to derive an electric capacity from the maximum value ( radius ).
>>110
Concretely, first, the frequency of an added alternating current is varied with an impedance device in a range of 0.01 Hz to 100 kHz at an optional current ( about 20 nA ) or an optional voltage ( about 10 mV ).
And, impedance values and differences in phase are measured under such conditions.
Next, the real component ( Ω ) and the imaginary component ( Ω ) of an impedance value are calculated out on measured values and a Nyquist diagram is drawn from those derived results.
>>111
So that, the resistance and the electric capacity of an oxide film, the resistance of a solution are determined by fitting those measured data to a Nyquist diagram.
Then, it’s better for improving its corrosion resistance and its biological compatibility to increase chrome and molybdenum added to stainless steel.
>>112
And, it’s more effective than solution treatment for accomplishing fatigue strength equal to that of a titanic alloy to add nitrogen and apply 20 % cold-processing to a material.
If an alloy made of Co-28Cr-6Mo is produced through a proper die forging technology, its fatigue strength and its durability are remarkably improved.
Industrial titanic materials are more excellent than stainless steel and alloys made of Co-28Cr-6Mo in biological compatibility, as micro-elements such as O ( oxygen ), Fe ( ferrites ) added to such industrial titanic materials increase, its fatigue strength rises.
>>113
Furthermore, if 20 % cold processing is applied to the fourth kind pure titanic material, its fatigue strength gets near that of a titanic alloy.
And, if molybdenum, zirconium, niobium and tantalum are added to titanic alloys, such titanic alloys get higher than industrial pure titanic materials in corrosion resistance and biological compatibility.
а
>>115
Moreover, if conditions of hot forging process such as over-aging treatment are rather modified in producing the material, fatigue properties of the material are far improved.
α-β type titanic alloys which are mainly used of the titanic alloys are composed of α-phases and β-phases.
※ α-phase has hexagonal close-packed ( hcp ) structure, meanwhile β-phase has body-centered cubic ( bcc ) structure.
Besides, Zr, Nb and Ta are mainly added to the titanic alloys which have higher biological compatibility than that of alloys made of Ti-6Al-4V .
>>116
Especially, only if a simple annealing treatment is applied to this α-β type alloy, the higher fatigue strength can be attained.
By the way, if a titanic alloy is produced with Zr, Nb, Ta having high biological compatibility, its dissolving cost tends to be expensive in comparison with a case to produce an alloy made of Ti-6Al-4V as a general industrial material.
Because elements added to the alloy are expensive. Accordingly, we must find out a dissolving process at low cost.
>>117
9.2-4 Equality in production process
First, alloys and elements are combined so as to satisfy a desired composition for producing an electrode.
An ingot is drawn from the electrode through two times of vacuum arc melting.
Then, the secondary vacuum arc melting is performed to make melted components uniform.
A homogenization to keep the ingot is applied to it at the high temperature of about 1200 ℃ for more than several hours.
Furthermore, blooming forging is applied to it at about 1200 ℃ to destruct its casted structure.
>>118
A structure at β-phase is optimized at high temperature without breaking body-centered cubic phases through β-forging to prepare an optimum metallic structure.
And, the temperature for β-forging is lowered to 1000 〜 1100 ℃ to refine β-phases.
Here, the temperature at which a structure in 100 vol % β-phase ( β-single phase ) is realized is regarded as a β-trausus ( T-β ).
And, the structure and its mechanical properties of a metallic material made of α-β type alloy are varied due to forging around T-β .
>>120
Then, if α-β forging is applied to an alloy composed of α-phases and β-phases at Tβ ( 30 〜 50 ℃ ), the alloy turns to be an excellent titanic alloy in strength, ductility and fatigue property.
10 〜 40 vol % β-phases in volume fraction are contained in an optimum α-β type alloy used at present ( about 2013 ).
>>121
And, if below 9 % Nb, below 5 % Ta of the metals having high melting points are contained in an alloy, it’s possible to melt the alloy through vacuum arc melting at present.
The production process in this case is same as that to produce an alloy made of Ti-6Al-4V .
If large quantities of elements having high melting points are added to a titanic alloy, some problems such as a sudden rise in melting cost, a quantity of remaining elements, segregation appear.
Accordingly, it’s needed to sufficiently guarantee the quality of ingot.
>>122
It’s possible to produce round bars made of titanic alloy within a short time at low cost through rolling process for round bar.
And, if models are molded from round bar-like materials through die forging, such a process enables improvement in yield.
Furthermore, durability, quality and mechanical safety of products can be improved by simultaneously performing plural treatments such as structure control, deformation at high temperature and molding through die forging.
>>123
Because, as the temperature of a titanic alloy rises, the tensile strength rapidly falls.
This character of a titanic alloy is used to realize more excellent deformation abilities at high temperature than those of stainless steel.
Variations in deformation ability of an alloy made of Ti-15Zr-4Nb-4Ta are equal to those of an alloy made of Ti-6Al-4V at β transus ( Tβ ).
>>124
And, the volume fraction of α-phase of an alloy made of Ti-15Zr-4Nb-4Ta is equal to that of an alloy made of Ti-6Al-4V at β-transus.
Accordingly, these both alloys are produced through the same process.
Furthermore, respective volume fractions of α-phase and β-phase are varied during die forging to modify durability of a material.
>>125
It’s possible to obtain desirable durability at the volume fraction in β-phase of about 20 〜 40 % .
And, an alloy composed of α & β-phases is more advantageous than a β-type alloy of a single phase.
Because the workability is remarkably improved in the former case.
>>126
9.2-5 Possibilities of downsizing of a femoral stem
A durability test on a femoral stem is executed according to ISO-7206-4 .
A stem is fixed with osteo-cement or mechanically at 10° adduction angle, 9° bending angle.
Then, the fixation position is defined so as to be 0.4 CT .
※ CT ;
A distance between the center of a caput and the end of a stem
>>127
Then, a sine wave is used as the test wave, it’s conditionally desirable to perform a test at load ratio ( minimum load / maximum load ) ＝ 0.1 , frequency : about 3 Hz .
The maximum load, the repetitive number to a breakdown are logarithmically indicated on a vertical axis, a horizontal axis respectively to draw L-N curves, and durable properties of stem are compared on those drawn L-N curves.
>>128
In this case, the larger the difference between a durable limit drawn from L-N curves and an allowed load ( an applied weight ) is, the higher the safety of stem gets.
If a load such as a weight is applied to a stem, a compression bending moment works on the stem at the same time.
Then, tensile forces are caused in the outside of the center of the stem, compression forces are caused in the inside of the stem, those forces get maximum on the surface of stem.
с
>>129
The following relation holds between the bending moment of a stem and the maximum stress on a surface of stem.
M ＝ P・S ＝ K・δmax・Z
. . . ( 1 )
Then,
M ; bending moment ( N / mm )
P ; load
S ; lever arm ( mm )
K ; stress concentration factor
δmax ; the maximum stress
Z ; sectional coefficient
If the section has a circular shape, Z ＝ π / 32d＾3 holds ( d ; the diameter of the circle ).
>>130
Meanwhile, if the section has an ellipse shape,
Z ＝ π / 32 d1・d2＾2 holds ( d1 ; the shorter axis of the ellipse, d2 ; the longer axis of it ).
The validity of ( 1 )-formula has been already confirmed through thermal elastic stress measurement ( in 2013 ).
>>131
The 10＾7 times fatigue strength of a material for stem is often adopted as δmax of ( 1 ) to evaluate the durability on the shape of stem.
Stress concentration factors at respective conditions are as follows.
・ smooth surface ; 1
・ stem coated with beads ; 0.8
・ stem coated through plasma-spraying ; about 0.6
And, it’s possible to downsize a femoral stem by improving δmax .
>>132
§ Conclusion
Huge costs are spent to develop artificial joints having excellent performance and to acquire pharmaceutical approval of uses of those products.
Such present conditions disturb those developments.
So, it’s needed to run steps from development to pharmaceutical approval as efficiently as possible.
It’s important for realizing quick judgment, cost reduction that respective sections including judging organizations cooperatively and industrial-politically tackle these problems.
>>133
In the past, in use of metal on metal type artificial hip joint, we partially focused on avoidance of dislocation, biological toxic risks including carcinogenic factors which were originated in cobalt ions eluted from abrasion powders of cobalt chrome were regarded as light matters.
We must understand respective matters under wide sight not to repeat such failures.
〈 An addition 〉
It’s desirable for preventing elutions of harmful metallic ions that a denser film is formed on a surface.
>>45>>48>>49
I heard that Toshiba Machine was changed into Shibaura Machine in name in April of 2020 .
This company was well-known in relation to ‘Toshiba-Kongsberg Scandal’ .
※ By the way, ‘Toshiba’ is the abbreviation for ‘Tokyo Shibaura Electrical Machinery’ .
141：Ground Stone Redux：2020/04/11(土) 23:27:18 ID:ICNvPh5c0
「An UFO ( Un-usual Flying Object ) crashes here and the wreckage was taken away by the local government in 1963」 http://www.oshimaland.com/?p=plzn8tjy
This case is very similar to the Roswell incident.
I heard that an UFO actually crashed at a place nearer to Corona than Roswell, but the wreckage was transported to a local governmental facility located in Roswell.
The year ‘1963’ more vividly reminds me of the following case.
「ケネディ・アメリカ大統領の銃撃現場 ( 1963/11/22 ) http://www.oshimaland.com/?p=9xlo8qxl
>>142
It’s likely that the harmful influence brought through「酒乱・大西共産党 ( The Great Western Communist Party )」such as Kodoku (蠱毒) drives the fellows habitually pasting undesirable advertisements on the net into bad behaviors.
>>143
I also heard that the fellows habitually presenting undesirable advertisements including vulgar or extremely erotic ones and fraudulent ones would fight against the world from now.
一
( 1 ) If a cat held on one’s back at an optional height is released to the floor,
the cat will get to the floor at a normal pose with twisting one’s body.
( 2 ) Here, it’s assumed that a position at an optional height corresponds to one polarizing plate, meanwhile the floor corresponds to another polarizing plate.
Then, a movement of luminosity through liquid crystal molecules packed into a gap between two polarizing plates is similar to the above motion of a cat in mechanism.
Meanwhile, we also heard that the people habitually presenting undesirable advertisements such as e×tremely erotic contents and unreliable ones dealing with defective products & fakes on the net would be conveyed to purgatories due to the judgment by the king of Enma (閻魔).
We also heard that the people habitually presenting undesirable contents such as e×tremely erotic & vulgar contents on the net would fight against the world as their enemies, and they would be transferred to purgatories.
